The tenkai palm is one of my favorites, if you can master the angels of it you can almost fool anyone because it is so natural. Anyways... The colour change: To make an affective colour change with the tenkai palm is just like this.
A) You palm the card using the tenkai, begin to talk to the audience a few jokes here and there to disarm their mind of you holding that card.
B) Hold the tenkai in your right hand then the deck with the bottom of the deck face up, so you can see the card. Example the 3C is face up.
C) Slowly bring the deck of cards towards the tenkai, to put it directly under.
D) Once the palmed card is on top of the deck you release your hand with a small motion, then cover the deck, then slowly end your trick by doing what ever you want from there.
I hope this is what your asking. And this is one of the beginer ways but there are several other ways too. I hope you understand these extremely confusing steps too
