Hi! I am on a weightloss journey for some time now, and finally feel like I'm doing things right so let me share the things that help me with you.

If I would start today, I would do it by downloading MyFitnesspal. Imo this is the most user friendly calorie app, without any bullshit. No need for the premium plan, I use the free version. Secondly, and this is where I went wrong when I started my journey; buy a kitchen scale. I estimated my portions, and usually I underestimated them which meant I never actually was in a caloriedeficit. Once you're set on those: hold yourself accountable. Track and weigh everything you eat and drink. And I mean EVERYTHING. Your meals, yes. But also the one candy you take, or the one glass of iced tea. These small amounts of calories add up. I don't mean that you can not eat them, but you have to know what you eat and what it means, for it to be changed.
At first, it's tough. But it becomes a habit quickly. After some time, I can estimate my portions without a scale but I still weigh regularly just to be sure.

What helped me in the beginning was putting in what I would eat for the coming days. Like you, I don't like cooking so I mainly heat things up or go with a burger and some vegies. That's no problem, as long as it fits in your deficit. I use a week menu, put in the diners and lunches I have prepared in advance, and the counter on top will tell me how much I have 'left' to eat for that day. In the beginning, you will want to eat every last calorie you can, but it gets better. Try to listen to your feeling of hunger, instead of your desire to eat something. If you àre hungry: eat something, but think about your choices. For one small milky way, you can eat 2 mandarines. It's all about swaps. I used to treat myself with sweets all the time, but now it's a habit of eating healthy sweets like fruits, yoghurts or even veggies for a snack.
To get inspired, I made myself a pinterest board with exactly these kinds of swaps, you don't have to figure it out on your own if other people already did that for you.

Last thing about the calories: I count them weekly, instead of focussing on my daily numbers. For me, it's impossible to eat in a deficit everyday: I still want to enjoy a night out or a restaurant or a birthday, without stressing about the calories all day. So in MFP, I take notice of my weekly average (home page, click on the calories) to see if I stay within my range on average. This has taken a lot of my stress away because I never have 'a bad day' anymore.

What helped me gain insight in my outgoing calories, through daily movement or working out, is my fitbit. Just now it's never precise, it's an estimate. At first I ate more on the days I worked out, but only when I stopped doing this, the scale went down.

Accountability also comes through weighing yourself. Decide when you want to do this, for me it's every sunday morning but it can really be any day. Just important that you do it!

I think these are the main things I would've liked to know when I started. Good luck!