I never shot a blowgun, so I can't really point you in the right direction.  There are a couple blowgun shooters who pop in here once in a while.  Maybe they'll be able to give you some good advise.

I can give you some general advise though.  I wouldn't worry too much about developing bad technique at the beginning.  For most things, the beginning is going to be bad technique no matter what you do.  The important thing is to be able to make adjustments when things aren't working well.  I think it would be worthwhile to check out a couple random videos on YT, give things a try, and see if certain techniques work for you.  In the world of primitive weapons, a lot of things are experimentation, self-learning, and rediscovery.

My method
https://youtube.com/shorts/EzxJgFvHNy8?feature=share