Beginner looking to create an iOS app that helps me curate and maintain a database of my watch collection – how should I starts?

I haven’t found a good enough app for this and so I’m thinking of getting it done myself. I have some experience coding in Python but nothing more than that when it comes to designing UI, building an app, connecting it to an online database, debugging, etc. But I am willing to put in the effort and build an app and deploy it on the App Store. How and where should I start?