Hello, and welcome! :3
Are you looking for techniques or just how to feed them?
Here's how to set I set my f/t up:
Take the mouse/rat out of the freezer and put in a zip-lock baggy and leave in the fridge the day before.
When it's the next day, take the bag and put it in very warm water (not hot, but warm), if the mouse/rat is too cool, put it back until it feels just about 98-99 ºF then blow it with a hairdryer.
(Note: Make sure the mouse/rat 99-100ºF precisely) Then feed your snake(s)!
If it's techniques you're looking for, you could try these if your snakes won't take f/t easily: (These are from my experience)
holding the mouse/rat by the tail and moving it in front of your BP
Wiggling it to make it appear alive
hold it in mid-air in dropping it suddenly (I saw this technique on youtube and it helped me loads)
These probably aren't all the techniques but these are some of the techniques I've had to use. (the first time I had used the latter)
If your snakes take f/t easily then you can skip this.
Good luck!
Also what do you feed your BPs? Mice or Rats?