Here would be your steps for using TennisPoint to help manage your ALTA team.
Here are your account setup steps:
Got a TennisPoint.com account already? Great, log into your account (or "sign up now" if needed) on ideally a computer browser to create a new team. http://www.tennispoint.com
Once in your account on TennisPoint.com, in the top navigation, click on the "matches & teams" and then select "Create New Team". Fill out the team's details (year, season, level, team name, etc).
Import your TennisPoint schedule from ALTA (blog article detailing how to import your team's schedule: http://blog.tennispoint.com/2010/05/20/alta-imports-schedule-division-standing-player-verification/)
Add your players to the team using the "add/edit & invite players" (link found on the "matches & teams") page. After importing in your team's schedule the player's names will be added to the top of the team... may need to do a quick copy/paste of your team's email addresses. Each player has a "role on the team" that allows you to make co-captains, captain or players.
Invite your players to signup on TennisPoint — easiest way is to send out the "send invite email to checked" from the "add/edit & invite players" page. (button at the bottom right of the page)
Have your players submit their availability for each match -- this way you know who is available to play each match and creating the lineup is quick and easy. FYI, the "invite email" mentioned in step 5 above does include this in the email to the players when the Team's schedule has already been created in TennisPoint.com.
Create a match lineup and send out a match confirmation email so all your players are alerted they are in the lineup — you can see the "match confirmations" from each payer as well and have peace of mind knowing that they will be at the match
After the match enter the scores on ALTA and then import your match scores on TennisPoint.