How to summon henchman?

I have done a search, but it would appear that this ? hasn't come up?

How does one use "a" or multiple henchman?

Thanks in advance!

Henchmen are standing around in town, usually near exits. You only need to invite them into the party as you would any other player to bring them along.

In the mission districts, there will be a row of the various henchmen types somewhere. Click on the henchman you want and invite them to your group like you would a regular player, and voila, you have a party!

Locate the henchmen in the outpost or city. Invite them to join your team. You can only have one of each type, btw. Enter mission/explorable area.

You guys rock. I will be on the look out for them!