Create member / use admin API in Budibase

I really suck at using APIs. Even when reading the doc, APIs alway confuse me and I never get how to use them properly. I’m using Budibase and I’d like to create members with it. Budibase can run bash and javascript automations but doesn’t support dependancies or npm require etc. All the code has to be in your JS automation ; no remote libs. It supports REST APIs ; but I really don’t get how to integrate them. Could anyone help ? Thank you so much !

Merry Christmas to you all !