Since you are going to be searching through Latin resources by way of medieval studies, the resources I’ve provided here are only cursory and most have translations to English attached to them.
A lot of references to older Latin literature are to ecclesiastical sources, sources relating to the Christian church. You might be looking for a sermon by one of the early teachers of Christian doctrine, known as the Church Fathers, or you might be trying to find a translation of something in the Vulgate Bible, or even just a single psalm from a manuscript psalter. If you are interested in books of hours or other liturgical literature, you might be looking for a standard Latin prayer translated into English. If you come across a term or an event you are confused about, the Catholic church has put a useful encyclopaedia online.
The Corpus Scriptorum Latinorum will have selected resources in their original languages as well as a variety of translations to accompany them. The Latin Library, on the other hand, is more likely to have whole works without translation. For purposes relating to this study, The Online Medieval and Classical Library is probably the bet on getting relevant information that is translated by scholars.