How do I add an external jar file into my mod?

[Gubipe]

I want to use discord rich presence for my mod, but I have been having some issues. This is what I added to my build.gradle file, but I do not think this works.
 

This does not let me build the jar file, but if I do not include it, then it does. However this has another issue. Whenever I attempt to start my game, it says:

  

[Gubipe]

I want to add discord rich presence, and the jar I use is in another folder.

[kiou.23]

you don't need to have the jar

just add the maven depency in your build.gradle, under where the minecraft forge dependecy is defined

then refresh the gradle project

Edited April 1, 2021 by kiou.23