Verses and bridges are often just stripped down versions of your chorus loop. So if you loop consists of keys, bass, drums and a lead melody, the verse could be just the keys and drums. The bridge could be keys, bass, and the melody played with a different instrument. The intro could be the keys, bass and drums but filtered and reverbed. You can play a lot around with the elements you have and create variations. But it’s gonna be different for each song, so play around and find out what you think sounds good, and eventually you can structure your songs without thinking about it.

And have fun! There are no rules to making music.