Scale question

Tl:dr: scale good, weigh items individually, try to be consistent in weighing either "raw" or "cooked" items, weigh oils, dressings etc..

Great question! I'm sure others will have more & better info, but as a *long-winded* starting point... I definitely recommend a food scale. It can help with education around portion sizes and can help identify where sneaky calories come in, much better than eye-balling or measuring in other forms most times. A good place to start would just be to weigh the food that you're currently consuming when you're aiming for 1280, to get an idea of their true calories.

As far as knowing how much food you need, this is, unfortunately, a personal matter unless you're following a meal plan of sorts. I do two different measuring styles.
My preferred method is to have a plan of what I'm eating for the day and log the big-calorie items to give me an idea of how many cals/macros I have for the remaining meals that day, or even better, log the whole day before it starts so I don't veer off track. But sadly;
My more frequently used method is to weigh as I go throughout the day and try to work my cals & macros on the fly *don't recommend*

For the preferred method, this will come as you get the hang of weighing things, I don't really recommend this straight off the bat as it can all feel a bit overwhelming. As mentioned, I'd recommend just weighing what you're currently eating. Unfortunately, in my experience, it's not likely to be the 1280 you've been hitting. It's more likely either a few hundred under if we're being too conservative, or a fair bit over if we're measuring with our hearts lol.

For a simple play-by-play of weighing while cooking:
For example, say you like to have an omelette for breakfast, where the cooked ingredients will be combined in the final product, so weighing the "cooked" version of the food would be a nightmare:
You would want to place a container/bowl on the scale, TARE it to "0.00g" (zeroing out the weight of the container so it's not added into your egg weight) then crack your eggs into the container to find their weight, log this as "raw egg" or "egg" or "scrambled egg" or whatever comes up in MFP, or better yet if you're using the app, scanning the barcode on the egg carton and popping in the grams you used, and it will give you the calories. You would repeat this for each of the other items/veggies you want in your omelette. For example, if you usually do half a tomato, cut up the half tomato and weigh that in a separate dish to see how many grams your typical half tomato weighs. Same if you're adding bacon, you'd chop it up and weigh it before tossing it in. Same again, scan the barcode on the package and pop in the grams you used.

Alternatively, if you're eating something pre-sized from a package like rice cakes, the side of the package will tell you a serving size is X number of cakes, which equals Y number of grams. I personally wouldn't weigh the rice cakes and just pop in the Y number the package gives me, but you could if you wanted to. For example 4 cakes = 25g which says 97cals, so I scan the barcode & pop in the serving size of 4 cakes to MFP. However, if I'm adding avocado and tomato on top I'll weigh those so I know their correct cals/macros/other info, rather than "quarter avocado, half tomato" as this will vary greatly depending on their sizes.

I will mention that if you're sticking to a calorie goal, you'll want to be measuring the oil you're using and any sauces as well as these can have an unexpectedly high number of calories if you're fairly new to the game. You can also look up a few recipes, most of which nowadays include the nutritional info, so you have a breakfast, lunch, dinner sorted and know what the cals will be for those, then pop in a cpl snacks to make up the remainder. With a low calorie goal like 1280, you may find exercise to be your best friend (from personal experience) as burning cals will let you eat more cals to break even at 1280.

A final thought; you'll want to be consistent if possible; whether you're weighing your food raw vs cooked, just always try to weigh it in the same form (raw/cooked) each time to simplify things for you. If you're cooking for multiple people, you may find it easier to weigh the pasta cooked, chicken cooked, etc. etc. rather than weighing it raw and then cooking a separate batch for yourself.

As far as actually using your scale, it will come with instructions. Measuring does take a bit of commitment at the beginning but it is extremely helpful when wanting to stick to a calorie goal, especially if you're not seeing much change.

You've got this, it's nothing you can't handle!!