I want to create my own version of AntennaPod with my podcast database

Is it possible? If “yes” what I need to do? Thank you!

this is a big question with very little details and not an simple answer.

if you wanted to do that, then start cloning the AntennaPod code on Github and look at the code that deals with the internal database

Why do you want to do that? AntennaPod can already subscribe to any podcast - so you can just add links to the website of your database where users can subscribe in whatever app they want.

Please keep in mind that AntennaPod is licensed under the GPL. If you want to do anything with it, you need to comply with the license.