I'm trying to add my husband but I don't know how to do it and connect everyone from his tree to mine. If someone could please help me that would be great. Thank you.
You add a spouse for yourself exactly the same way you add one to any other profile: using the "+ Add Spouse" button/link below your name in the "Spouses and Children" column of the Family Members section of your profile's Details page.
You'll need to use the "By Name" option on the popup, since profiles of living people are private/unique to the user account that enters them, but given that you're the only one who will be seeing and using the profile, you don't need to bother with the details. (I haven't even put my surname or birthdate on mine.)
Once you've entered your husband, you can go to his profile and use the "+ Add Parent" button/link to hook him up to his parents, etc. If they're still living, then again, you can just treat the profiles as placeholders; if they're deceased, you'll want to find them in the public part of the collaborative tree, and you can use the "By ID" option on the popup to make extra-sure you've got the right profiles.