I need to popular this database to conduct test queries for educational purposes.
I already have about 5 students, 2 teachers, but the problem is to popular the exercises manually. Is there any more practical way?
Good as you mentioned Excel. There are websites on the internet that convert CSV files into ready-made SQL Scripts. Just tell us the file and some parameters he asks for.
This site (SQLizer) does this very well I've used several times.
As you commented that it is for didactic purposes time to transform the data will not be problem for you (I believe)
Just have the files in excel and the site generates the script ready to load in SQL