Well, I don't think those "frog" sounds are useful for us, beginners. I'm sure we wouldn't feel the interest physically. Anyway, no one can do them properly before being close to sing perfectly "normal" high pitched notes. You would just end performing "attempts", or uncontrolled sounds, which is in essence useless. It's like, trying to play master of puppets when you just got your first guitar yesterday. And, the day when you will be able to be close to this, I'm sure you will have no need for somebody to explain you how to train.
I'm not a pro, but I suggest you mainly train on normal training on range of your vocal performances. Improving your high range could improve your overall singing performances, whatever you would sing. A lot of singers are capable of many things they never use.
I am myself personnaly interested in being able to growl or highpitch growl, but for the moment, I'm focusing in lerning the basis of every singing technique. It's much more interesting overall than just training doing growl all day.
Also, even myself don't train too much on it, but warming up 10mns a day, and singing scales 10 other mns a day, can improve your singing dramatically.
I'm not myself a good singer for the moment, but those philosophical things are stuff I have learnt here and there, from my teacher or from friends, or from various sources.