To the right, under the Assigned to Teams drop-down, select the Program from the drop-down.
Then, select the team(s) you'd like to email. If you would like to email more than one team, hold CTRL as you click each team name. If you'd like to email all of the teams, click the first team in the list, and hold Shift on your keyboard as you click the last team in the list.
If you'd like to narrow the selection more, use the form to query further.