In a standard slam, you have three minutes to perform. If you go over, you lose points. Judges then give you a score out of 10, and the poets with the highest score go through to the next round and perform again. There can be many rounds or just one.
Judges may be invited or may be people chosen at random from the audience.
Slams are fun, energetic and loud. I’ve only just started to dip my toe in the water. There’s an assumption that you need to do a poem about your trauma to win, but in my experience this isn’t the case. Slams are as varied as the performers.