I posted this in another thread:

My, totally non expert, advice is that you should just start by making sure what you eat is healthy (good macronutrient balance, not too much sugar or refined carbs). Don’t worry about exercise or how much you eat, as long it’s the right stuff.

Once you’ve settled into eating healthier foods, count calories for a while, to see how many you’re getting. You may already be getting a good amount. If not, consider whether you should adjust your portion size or meal timing. Less carb-heavy foods don’t hit you with that full feeling as quickly- often you’ll eat, still feel hungry when you’re done, then half an hour later you’ll realise you’re not hungry any more. So don’t wait until you’re ravenous to eat. Experiment with eating less and see if you’re still hungry

At that stage if you’re getting too many calories you probably need to do the hard steps- exercise and/or cutting down further on meal sizes spending significant amounts of time hungry. Bad, but remember it’s not permanent- once you’re at your target weight you can start eating at your maintenance level.

How difficult it all is depends a lot on your psychology and physiology, so good luck.

Subsequently found this site, which has really good articles (unfortunately with a lot of clickbaity salesy ones mixed in): https://www.precisionnutrition.com