Since I’m at the stage in which I have to start applying to uni/college, there is a school I’ve had my eye on but it has a religious affiliation and I don’t follow any religion. How much does this affect overall school life? What’s different/the same?
thank you! 
It varies hugely. No one can tell you without knowing the name of the college.
I’m looking at Loyola Marymount University for now!
I don’t go to LMU but I know loads of people who do (I live not too far away) and I can tell you that it’s not really a big deal. You can (and should if you like the school) still apply there.
Loyola Marymount is a Jesuit college, which means they will require a theology class. However, these aren’t Catholic-indoctrination classes or anything; there are usually options about how they can be fulfilled (not all are Catholic theology, either). The Jesuit identity will inform campus policies, especially in the realm of service, which is very important to the Jesuits. There will be a lot of emphasis on community service. If you want a totally secular college experience with no reference to religion, it’s not for you, but Loyola Marymount isn’t one of the institutions which requires chapel attendance or anything like that. (My information comes from the 60% of my relatives who went to Jesuit colleges and my cousin who works at LMU)
If you like the school and aren’t upset by the presence of religious imagery or language, then go ahead and apply! It’s a great school.
My S went to a different Jesuit college. The Jesuits are educators first and foremost. Religious outlets are available for those who wish to partake but religion is not forced on anyone. IMO the bottom line is 1) you should be respectful of religion but you don’t need to practice the religion 2) you should be OK with seeing religious symbols on campus and 3) you will likely have to take theology and philosophy course as part of the core curriculum 4) there will be some unexpected things dictated by religion (ex. no birth control is given out on campus). If you are OK with those things, then you should be fine.
The credo of the Jesuits is Men and Women for others. So community service is important at the Jesuit schools. Tolerance for others, also promoted. Theology requirements vary, but it is usually just one class and many of the theology classes offered are structured more like history courses. A philosophy course is required at many Jesuit schools as well
^^^My S had to take 2 philosophy and 2 theology classes at his Jesuit college but it does vary from school to school. If it is a factor, the OP should google the LMU core curriculum and get details on that college’s requirements.
My brother, an atheist Jew, goes there. When a Jewish friend and I visited him in his dorms he said that most students aren’t super religious.