Just got braces today? You'll be fine.

It'll last only a few days, at most. Based on what Reddit has said and in my personal experience (currently have braces), just chew and eat normally after each tightening appointment (and of course, initial appointment). It'll be a little more painful, feel a little more tense and tender, but by working your teeth then it goes by a lot faster. And honestly, it's not "painful", you know?

Since it's your FIRST appointment I would recommend primarily eating soft foods (smoothies, yogurt, etc.), but be quick to involve 'normal' food and eat as you normally would. I personally, even after months of having braces, find it hard to chew as much as I want to with bite blocks on, but eh I guess we'll get used to them eventually.

Best of luck.