With your project team members
Hi @Dominika Kuraś-Moskwa [Deviniti] ,
Every group is best in one or the other way. It all depends on what you need from Community!!
I joined product groups and local groups. All groups are listed in https://community.atlassian.com/t5/Groups/ct-p/groups
If you are looking to answer different user queries, then go to https://community.atlassian.com/ and select the products. You will start seeing the posts/questions/articles next time when you open https://community.atlassian.com/