I’ve made two short films about how to prepare a canvas for use with watercolour, which I hope you find helpful. It’s very straightforward and sounds far worse than it is!
The first just entails putting on three, thin and even layers of watercolour ground – then letting it dry.
The second method creates a really textured surface using tissue paper, which I used to paint this swan:
Again, it’s not tricky, just takes a little time and patience.
If there are any techniques you would like videos of, let me know. My digital skills aren’t great, but I might be able to have a go!