Open games refresh every few seconds. Private rooms are not listed — those need a code.
Ask the host for their 5-character code, or just open the link they shared.
Map
You'll get a 5-character code and a link to share. Untick the box above to keep it code-only.
Settings
High adds ambient occlusion, bloom and a captured sky
(a ~1 MB one-time download). It looks considerably better and costs frame
rate — Medium is the safe pick on a laptop.