Joining a group is as simple as clicking on Groups, followed by Find Public Groups. Once you are there you will find a listing of suggested and publicly available groups. You can click on the group title to peek into the group and determine whether or not you would like to join.
After joining a group their updates will appear in your Home feed, but you can also post questions or ideas to these groups and likely find very helpful responses from teachers all over the world in teaching positions like yours. A few groups I would highly recommend joining are Schoology Educators, Blended Learning, and Flipped Classroom.
Thank you to Nicole for turning me on to these!