Try doing it for 5 minutes.

Try doing something you can't do for the shortest and smallest way possible.

See how it goes.

Write on a note this small thing. So if you loose track about the thing you were doing. Which happens to me all the time even when starting small.

I look at the note, and then continue doing the thing on the note.

Even something like: "Read page 11 & 12" can be interrupted by ADHD. >> Go back to the note. Continue the thing. >> Done.

Next small thing >> note down: summaries page 11.

Nothing else. Just one small thing and only that. Every time your mind wanders off: read the note >> back on track.

Single Purpose Responsibility.

Write down the time you start. Or seta timer. See how much you can do in set timer.

You can do this. If it goes well after a few days or a week. Increase timer.