u/WarWithReality

What is the correct sequencing of commands? For example: I am the active player and my charge phase just started. My opponent wants to use a command which let's them charge with a unit during my turn.

Can they use the command instantly? Do I get to charge all my units first, then they may use the command? Or does my opponent have to ask if I have any commands I wish to use, then do the usual "you go, I go?" sequence for abilities?

Please help clear this up.