Look up Kagan for group work. Basically gives kids roles in the group so the group can't be successful without 100% participation. Don't get it wrong, they're kids, they'll still slack off. But it is less, and the teammates will actually give a shit if one of the kids is slacking off.
Also, you are not alone in kids reading below level. I would dream for 1-2 grade levels below. The HIGH kids I have are at grade level. A SOLID chunk of mine are demonstrably entirely illiterate in 7th grade. It is what it is. Get them reading, keep them reading things at their grade level, don't let them read easy things like comics. Most kids don't have the intrinsic motivation to make good choices with their time, you have to make them and check up on them. If you have software to manage chromebooks (GoGuardian) learn to use it, and use it well. Teach them nonfiction reading strategies (get your boss to buy this, or something similar) and force them to use them.
Don't worry too much about doing the curriculum 'correctly' if your admin isn't micromanaging you and giving you resources it's because they expect you to do it on your own, and are aware that your class will have your unique flavor. Just cover the skills and standards, grade based on grade-level competency of said skills and standards.