TDEE, what is it and how do you use it? Help me please! :)

Okay. So, it seems amazing to me that I have to eat 2688 Calories according to TDEE? Right now I am at about 1500-1800 calories give or take and I work out 30 minutes a day 5 days a week that consists of walk very rapidly, and some small basic calisthenics. My current weight is 259 and I am 5'8 and at 30 years of age I am currently working a desk job. I want to lose about 2 lbs a week, more would be great but I want to do it the healthy way. I recently started to hear about TDEE, so I've checked into the websites but I really don't know exactly how to use this information for my advantage. So here are my questions- Do I really need to eat 2688 calories, if I do- how do I fill that without putting myself over in fat, sugar and sodium content? Do you have a website or some kind of reference you can link so I can gain some further knowledge on the subject?

Thank you in advance for your response and I greatly appreciate your help.