Knitting fingerless gloves with circular needle. Thumbhole?

[parrotonmyshoulder]

I’ve just learned how to use a circular needle and trying to make wrist warmers/fingerless gloves. I can’t find a simple tutorial for making the thumbhole. I have read patterns about binding off, knitting back and forth, but can’t understand it!
Any easy ideas? These first ones are probably just going to be tubes without the hole, but I’d like to know how to do it.

I use magic loop method. should be tutorial on YouTube

The afterthought thumbhole method might be best to start with, there will be some tutorials on youtube. You get a bit of scrap yarn to knit your thumb stitches with, and then pick up the stitches after finishing the main part of the mitten.