How to get access to these end points?/ Can you give me access to one of them? I will be messing around with data a bit and try to integrate it into my bot. I'm not too familiar with RESTful APIs so please include as much details as possible about it

It's a simple HTTP request:
https://api.ninjastic.space/posts/55141939Status code 200 means the post exists and you can parse JSON. 404 means not found, etc.