Implimenting interfaces and libraries in a contract

I have interfaces and libraries in different files and folders,
I want to use them in a contract in my project,
how can I use it ? how do I import them to my contract file?

You can use interfaces and libraries from other modules and crates as long as the modules are publicly accessible (pub), and you can shorten the paths with use. See Cairo book Ch7.

For external dependencies, check the Scarb Documentation.