You can start with the main search on the library homepage, which includes a range of databases, and then move on to some of these databases.
Think of your search terms. If you want just a few good things, you can use just one or two terms, but if you want to make your search wider, you can try more terms.
Try, for example: "first nation*'" or aboriginal* or native* or indigenous or indians
In many databases, quotation marks mean that the search words are searched together as a phrase, for example "first nations" will just search for those two words next to each other. An asterisk can help you search for words that have the same root, for example, indigen* searches indigenous, indigenize, indigeneity etc. BUT will also search indigent.
You may find other library subject guides useful - for example, English for Indigenous literature, Art, Drama, Social Work, Law, Health, Education etc.