In hindsight what helped me back in school was having someone to study with, maybe that could work for you?

Ask her about the topic. Learn a little yourself and show a genuine interest then ask for her help understanding it. This creates salience in the learning for her and also shifts her from arbitrary retention to learning to explain to you, so the mental structures are much more dynamic.

I would also recommend finding interesting things that are on the other side of understanding that material. For example, what is in the next unit? What cool things will learning this stuff unlock? It is not always the best strategy especially at the start of the unit, but as you get towards the end of the unit it can help bring the focus back to getting through the exams.

Do not try to become her manager or parent or psychologist or coach. It will negatively impact your relationship.

https://www.getinflow.io/post/adhd-authority-issues-defiance for some ideas on why.

If you have a problem with how she is behaving, you will not be able to change it through external influence. If she really has ADHD (emphasis on disorder where it is negatively and significantly impacting her life AND is diagnosed) and is unmedicated, the single best thing she can do is get medicated, and that’s her choice. If medication isn’t working, she should talk with her provider about it.

If she requests help, feel free to provide it. Feel free to ask her (and not internet strangers) if there’s something you can do to help her as she’ll know what works and what doesn’t as ADHD isn’t a monolithic diagnosis and what works for one person might drive another up the wall.

Sorry if this seems a bit negative, but I was in school when all the Where There’s a Will There’s an A and all the techniques in the world did not make a difference to people that can’t utilize them, but they can frustrate and shame people.

Look up classic ADHD coping mechanisms. Others have mentioned some in this thread like studying with someone (body doubling) or enforcing a schedule. One big reason procrastination works is that the stress/adrenaline acts like a stimulant that is one of the normal medications for ADHD that helps you focus.

One other suggestion is to study when well rested (first or second thing in the morning). ADHD symptoms can be exacerbated by being tired.