Android and SQL Database

Currently making an app for the very first time, its a massive learning curve for me and the results are satisfying.

So at the moment I have my design all set up, now I need to work on the database side of things.

I have found all the basics to creating tables and adding entries, however I'm a little unsure where I should be inserting this code.

My queries are:

=> Does the code for creating the database tables, inserting/editing/deleting data need to have its own class, separate classes or is it all be done in the class of the 'Form' I have created.

=> How do you connect to the DB so I can call the results, does this need its own class also for showing the entries or can this be done on my 'Entries' class.

Working with android studio, if anyone can give me a better understanding would be much appreciated.