There are two types of groups .. I call them DS Groups and MEMBER Groups. DS groups are those offered by DS itself and MEMBER groups are created by members.

The following is from the HELP PAGE:

"How do I join a group?
You can view, explore, and join any public groups. Private groups are unlisted, and can't be viewed."

but then they say:

"Are there private Member Groups?
We're starting out with public Member Groups, however we expect to add private at a future date. Private groups will only be visible to the founder and invited members."

Nowhere in the HELP page do they tell us how to list or find groups.

At the top of the HOME page, is a tab SUPPORT GROUPS. That tab lets you find any DS group on the site. To find any MEMBER group, over on the right side is "View all Member created Groups". Between these two facilities, you should be able to access any existing group on DS.