SQLite JDBC - How to populate new Database

I was given two databases, and am supposed to create a table in a new database that stores information about the given databases. So far I created a table in a new database. I also defined its attributes, but I am stuck on how to populate this table.

The attributes are things like 'original_db, 'original_field' etc , but I don't know how to access this information? Especially since I would need to connect jdbc to 3 databases (the new one, and the 2 old ones) at the same time. Is ths even possible?

I am new to working on databases and SQLite, so sorry if this is a stupid problem. I would be so grateful for any advice!