Display custom post

Hey,
Im pretty new to wordpress.. and doing a school project.
I managed to add custom post and custom fields, but struggling very much with displaying content.. is it because of the theme that im using? (accesspresslite).

I don’t understand which file i have to code on to display them.

I’ve also looked up and know it is possible to make custom posts by hand. But when using theese plugins where does the data saves? is it under WP-content/plugins ?

https://ww.wp.xz.cn/plugins/types/