Currently I use sheet of paper, pencil and eraser, but it is just a bit tedious, especially when making things more detailed.
Just text example with different levels of detalization:
Drink water from bottle
Drink water from bottle
(Take bottle -> Open it -> Drink)Drink water from bottle
(Take bottle -> Open it (Unscrew the lid -> Put it aside, don't loose it)
-> Drink (Move bottle to mouth -> ...))
And so on...