Right, first off go through and complete the basic tutorials on the Bubble website - this will get you started.
Then you might want to follow some more advanced courses, like over at https://www.codefree.co or this Udemy course:
At some point you’ll need to start getting familiar with the Bubble API:
https://manual.bubble.is/using-the-bubble-api.html
As well as API docs for the major social media platforms:
My advice, start slow, built practice apps and gain confidence. The Bubble learning curve can be steep depending on your background… but most people start to really make progress after about a month, sometimes less if you throw yourself in full time