Looking for new data and Update Database

I’m about to make my own Payment & Balance dashboard with data from Stripe.

I have Connected to Stripe Via the API connector and I can fetch data from it, and show that data in my own dashboard. (I’m super excited it’s my second day with any code and bubble)

My question is:

I need to look into the stripe database for new payments and if there are new payments I need to only import those and not the whole database of payments again.
Because now I can only fetch the data there are and when I do it again it will duplicate the data.

And at last, is there a place where I can learn about how to build proper databases and learn the structure behind it?

All the best
From a new bubbler.