Hi everyone,
I have completed learning Selenium with Java for automation testing.
Now I want to learn API testing, preferably using Postman [I KNOW BASICS ]and related tools.I am looking for learning resources, tutorials, or project ideas that can help me get started.Any guidance or tips from experienced testers will be highly appreciated.
Thanks in advance!
Welcome to the Postman Community! 
You could try taking a look at some of the self study courses that we have on the Postman Academy to upskill your Postman knowledge.
Also the Postman API Fundamental course is something that can be taken which provides a certificate and badge when successfully completed.
The public 30 Days of Postman course is still available to work through and learn various different Postman features.
We have a great selection of videos on our YouTube channel that cover a wide range of features and topics - It’s well worth checking out!