I actively practiced with whatever tool gnome had built-in at the time, it’s called klavaro or something. It’s a very simple practicing app.

It took about two weeks for me to get familiar enough to be able to work in it without having to switch back sometimes.

The trick is just like with learning a new language: don’t switch back unless you absolutely have to, not when it would be convenient/faster.

Within a month or two you’ll be typing Dvorak like you’ve never even heard of qwerty.

Some things to note:

At the time I learned dvorak I was not fully typing qwerty with ten fingers, so ymmv.

I’m actually using programmer’s Dvorak; the difference is in the placement of the non-letter characters.

I don’t necessarily recommend it over regular Dvorak; if you find yourself regularly using other people’s machines, I’d probably recommend against it. Every major OS has Dvorak built-in, but not programmer Dvorak.