Forget what you've been told about sitting crossed legged for twenty minutes and trying for a "blank mind." That sentence alone was dreamed up by someone whose brain has only barely a few tabs running at once, crimson desert how to meditate.
The ADHD brain thrives on dopamine and novelty, and a stream of sensory information, so the opposite of those things (stillness, silence, repetition) when requested of us, would in most people cause them to feel like something's wrong with them — like everyone else would; but also feel like an immense failure. Which, again, does never really come from willpower — it comes from using it the wrong way. Two minutes is the target.
Don't reach for ten minutes.
Genuinely aim for two minutes instead; which, in the first 30 seconds of which, you are going to drift off in some kind of spectacular way anyway; so with all due respect — the less runway you have when it first zooms away, the less time it has to pick up too much speed,and you can reel it in! Success is simply coming back,and this is your entire rep. Doing the rep for 50 occasions throughout two minutes,you would most certainly generate greater mental focus than someone who just quietly sat for twenty minutes on the floor —totally aware of absolutely nothing.
Movement works wonders; a walking practice, dancing, even pacing your floor or the house; or any kind of movement while working on mindfulness... Any of it counts! Attempt pacing the house or the room with a fidget object and just focus on your breath when it would not be a good situation at all,if anyone in the world were to watch your behavior! Whether you buy it or not... "tidy up the kitchen" meditation (water running, hands occupied and mind in its body) is often times how the most present, intelligent minds actually find bliss with meditation instead of a picture-perfect, straight-out-of-a-yoga-magazine, meditative bliss pose.
Noise can be another lifesaver where true silence becomes almost unbearable in an ADHD brain. Put on your favorite guided sessions, binaural beats, or even just the sound of the clocks ticking in your room and your brain will handle the rest by fixating on whatever thing it's listening to!
Timing of this meditation session during your day matters too... Should you have prescription medication that you take during the day then this is often times a much better time than right when you wake up — when your brain is not exactly ready at all.