You do need a basic picture of what is going on with your food intake. I say basic over detailed because many keto recipes come with incorrect or incomplete macros. Plus many macro apps will provide different results, so take precise macros with a pinch of salt.
That said the best way to make sure you’re staying under 20-25g net carbs per day is to have some kind of system for measuring and tracking everything that you’re eating each day.
The best technique to accomplish this is to purchase a food scale and use a macro tracking app where you log what you’re eating using a keto diet app such as MyFitnessPal.
As for managing your calories, in order to lose weight consistently, you need to create a caloric deficit, so you should figure out what your maintenance calories are, and then subtract 15% to 25% from that number, to get your caloric goal. It is a good idea not to use multiple diet apps since they rarely provide the same macros.