I know you've put a out a couple of open and altered tuning lessons, but can you do a lesson about it in general. Like, how to tune to the various tunings and what to do with them. Thanks!

That would be like a series of lessons. There are many many many altered tunings, and the possible things to do with them are almost infinite.
In metal you have many altered tunings with the drop 6th, in acoustic you have a lot of different tunings to play different songs but that depends on the composition. For example, Laurence Juber has a clinic about an hour and a half only with tunes with the DADGAD tuning.
Ian Bushell have a "drop C lesson" and in other lessons he uses alternative tunings. Carlos Carillo have a D dropped lesson. The lessons I've made of percussive guitar have that the DADGAD tuning, so for that you can watch them.
Now I'm working on some new acoustic lessons that uses other alternative tunings.
Also you can check Jimmy Page playing, he uses a few alternative tunings too.

Thank you Raph for your request



This is true. A lesson about all the open tunings is simply impossible, since they are too much.
I'm working on my Jazz Notes series but I'll do some other lesson about this topic in the future.