When you get the combination module as you equip the module, scream into the mic as loud as possible "FORM VOLTRON!!!" and then fight the King Titan blah, blah, blah, and hope it doesn't kill you.
To tame one , you go to the studio wildcard hq , reee so loud that they listen to you , then feed them dodo kibble until one of them dies and then torture one of them to tame a Mega Mek for you .