I’m basing my answer off the code that’s in your screenshot. Assuming that code is working correctly, it is saying (I think) that if a WordPress user has an active membership in the groups that have the ids 10730, or 10732, when they log into Discourse, they will be automatically added to the Discourse group with the name “basic”.
The WordPress code may be configured so that users will be automatically added to the Discourse groups when their membership level changes on Discourse. I can’t see that code in the screenshot though.
From looking at the code, my assumption is that the WordPress memberships that are meant to add users to the Discourse “basic” group have already been created. They will be the Memberpress groups that have the ids 10730 or 10732.
It might be worth double checking this with the person who wrote the code. You can also copy the full code and send it to me in a PM if that helps. Note that I don’t currently have WordPress setup locally, so I’m not in a position to test it.