You first need to figure out where your team's home games would be. Look into the local facilities and see what it would take to reserve the courts for matches. You may need to join a community tennis group or club to be able to reserve courts. And some clubs require that some number of players on the team (ranging from all to none) are also members of that club. Courts fees are usually shared amongst those that play, so you shouldn't need to cover the court fees all by yourself.
You also need to join the USTA if you haven't already. Your local area probably has a website that gives the dates for when team signups start and end for your area. Signing up a team is free. Signing up to be on the team if you are captain is also free. The other folks signing up costs somewhere around $20 a person for the season. They also have to be USTA members first. Before you sign up for a team you need to ensure you have enough players to make the team viable, because as a captain, if you sign up a team, and then don't drop it before the deadline, and have to forfeit a ton of matches because you don't have enough people the region can restrict you so you can't play or captain for a year or two. (In our region they usually just say you can't captain again for a few years...) So if you found enough interested folks, just sign up the team on Tennislink when the window opens, and have people start signing up when membership opens a few weeks later. Just a helpful hint on the selfrating. Follow the experienced players guidelines, but if you haven't played successfully on a high school team or better, you might consider self rating at 3.0 but still captaining and playing on a 3.5 team. If by chance you overestimated how even you would play in 3.5s, next year you could play 3.0s (or you might even be able to join a 3.0 team and play both levels.) Sometimes the computer is very slow at bumping people down, and players can get stuck in the situation where they over rated themselves at the beginning and can't get to the correct level. But you of course can play up.
Once the signups are complete they determine leagues, and then you get to email or call the other captains to set up dates and times within the week they give you. There are usually some restrictions, like weekday matches must start between 6pm and 9pm, weekend matches must start between 9am and 4pm, or something like that. It's easiest to pick a regular day and time for your home games for each week you are supposed to be at home, and reserve those times, and then tell all the other captains. Usually the other captains are happy with your times, if not then you can change the one or two they have problems with. Be reasonable on the times they send you and you are more likely to have pleasant matches.
Once the schedule is set, if you are just going out for fun and not to win the whole shebang, send out the dates, see who's available, and then assign matches as fairly as possible. Remind them that if they can't show up they need to tell you, so you can get someone else to play. If there are some matches you can't fill, it's time to go out and recruit more people.
Then it's just a matter of printing out the score sheets, showing up, and having a good match. At the end you can offer to enter the score sheets. (In general the winner will want to enter the score sheets, as if no one enters them you both show up as losers.) The system will walk you through that.