The Garreg Mach monastery is located in the heart of Fódlan. The monastery features a large cathedral dedicated to the Church of Seiros, as well as the Officer's Academy. The structure acts as a home base throughout the story, and characters often return to the monastery to prepare for each chapter.

At the beginning of the game, the player (previously a mercenary working with their father Jeralt) rescues a group of students from the Officer's Academy from bandits. These students happen to be the house leaders of the three classes at the academy, and bring the player to Garreg Mach to meet the Archbishop, Lady Rhea.

Rhea decides to appoint the player as a professor at the Officer's Academy after a somewhat biased recommendation from Alois Rangeld, a member of the Knights of Seiros. The player is allowed to choose which class they would like to teach, and the story begins to take place.

As a professor at the Officer's Academy, the player is free to explore the monastery during free days of the month. There will often be a few free Sundays during each month where the player can choose to explore, this is known as the Explore Phase. During this free time, the player can choose between many different activities such as conversing and eating with students, helping with meal prep, fishing, gardening, choir practice, or even just walking around.

Walking around the monastery and interacting with students and other faculty members will help you build support with them. Once you reach certain requirements, you will be able to recruit characters from other classes (and even the Church) by talking to them during the explore phase. The player can also find random items scattered around the ground, including consumables, lost items, gifts, and more. There will also be various quests available each month. Required quests must be completed in order to progress in the game, and normal crests serve to increase the player's renown and professor level.

Aside from talking to students and faculty, there are a lot of different activites that the player can partake in around the monastery. Most of these activities lead to some sort of benefit, such as increased support between units and items. The player will have a limited amount of activity points for each free day, some activities will cost activity points and some will not. The "free" activities should be taken advantage of every explore phase, since there is absolutely no drawback and the rewards can be pretty good. See the below table for a list of activities and their activity point cost.

To get the most out of every explore phase, check out the following guides on different monastery activities.

Besides from the exploring, the most popular option for free days is battling in auxiliary battles. If the player chooses this option, they will be allowed to take part in a number of auxiliary battles based on the professor level, up to a maximum of 3 (information about this in the next section). Auxiliary battles are generic battles that usually involve repelling bandits or quelling Western Church rebellions. Occasionally, there will be harder battles available (marked with a red exclamation point), where the player can battle against stronger enemies that include a demonic beast and receive crafting ores as a reward.

If the player accepted any battling quests during a previous explore phase, they will also show up as options in the battle screen underneath the other auxiliary battles.

Battling can be a great way to boost your units' levels to prepare for the monthly mission. Battling is also the most effective way of training an individual unit's skills, although it likely means that you will somewhat forfeit the following lecture session by not raising the motivation of students. Because of this, it is recommended to only battle on the last free day of the month, right before mission. There is never a lecture session after the last free day of the month, meaning you won't be sacrificing your students' education for level ups. The only thing to keep in mind here is that after the Chapter 7 mission, there is immediately a lecture without a free day before it.

One thing to keep in mind is that frequent battling will likely make your units extremely overleveled (especially in normal mode, where you can retreat while retaining experience), making the actual game chapters quite easy. This is less of a problem in maddening, since experience gain is greatly decreased. Players seeking a challenge may wish to avoid battling on free days.

Attending seminars allows the player and a handful of students to gain a reasonable amount of skill experience by attending seminars led by faculty members (and students during War Phase). The player will always attend any seminar, as long as they are not the instructor. Students who have innate interest in the seminar subject, or have goals that match the subject are more likely to attend. Increased motivation also improves the chances of a student attending a seminar.

Attending seminars is one of the only ways for the player to gain skill experience. The other methods being faculty training (advanced drills in War Phase), and battling. Since seminars take an entire free day, they are often worse than exploring. Training with faculty members and students while exploring only costs one activity point, although the experience gained is usually less than seminars. This is usually the preferred option, since it opens the player up to doing more with their free day than just gaining skill experience, such as gardening and eating with students.

The final option for free days is to simply take a break and rest. The value gained gameplay-wise from resting is that the Sword of the Creator will replenish 5 weapon durability, and all recruited units will gain 2 motivation points. The regular Sword of the Creator is not a particularly amazing weapon, so it's almost never really worth it (especially since it can be repaired at the Blacksmith), although resting does see some situational use in various LTC strategies.

Another reason to rest on free days is to get through the academy phase faster, this is sometimes done by players who want to see the other storylines in the War Phase. Resting often will also significantly increase the difficulty of the game, since your units will be underleveled in both stats and skill experience.

It is recommended to avoid resting on free days for players who want to optimize their playthroughs.