You can view your team/members via this icon in the left hand panel:
Once you click on your team name, you should see the option to Add members:
To share content with your team, ensure your activity(s) have first been added to a folder.
To add activities to a folder, select the item(s), click on Move:
Select the folder to move your items to:
Once you have moved your content to a folder, click on the three dots to the right of the folder, then click on Share:
Select the team(s) with whom you would like to share your content with:
Click Save.