Hello there! Can anyone please tell me how to make a new discussion? Thanks!

It seems like you made a new discussion here already so you should know.
To review, go to any forum category. On the top right, click on “New Topic.” Fill out the necessary stuff for your discussion and click on “Submit” to submit the discussion to the forum.

You can’t make an entire forum. If you were talking about topics/posts, you literally just made one.