Creating a team begins with either upgrading your original account to a Teams plan, or by creating a new account and giving that account a Teams plan. You can also have basic team of up to 5 reviewers (view-only access), on the Professional Plan.
Once you have done so, you can begin adding members to your team.
Once they have accepted their invitations, you can begin collaborating by assigning these members to folders.
If you don't have any folders, you will need to create a new one (the "Active" topic folder is your default folder which you cannot share others on), and then either begin creating topics or collections in that folder, or move existing topics into that folder.
Folders are how you control which team members have what level of access to your topics or collections.
Your team members should then be able to access and interact with those topics or collections, and the suggestions within.