Does anyone have experience repainting kitchen cabinets? I could use some advice, and if nothing else, some calming down about this..

We just moved into a new house. I absolutely love the place, it's fantastic โ€” except for the kitchen. It's not a bad kitchen, but it needs some work, and the boyfriend and I agreed that if we were going to take this place, we were definitely going to make some improvements on it. The biggest thing that will give this place a bit of a facelift is the cabinets/countertop space. The walls in the kitchen are kind of a nice seafoam green, and the owners made the horrible decision to paint the cabinets and countertop just a few shades darker. It looks very odd. Plus, it's all kind of in bad shape and needs to be repainted anyway.

I decided I want to paint it all a nice eggshell color. The thing is, I've never done this. I thought it would be as simple as, buy some paint, put it on, boom, done. I fell into a Google rabbithole about repainting cabinets and now I'm freaking out a little. There are so many steps and choices and I have no experience in any of this and it's kind of overwhelming. Apparently I need to sand everything? And use primer? And what the hell is the difference between latex and oil paint? And how much of everything do I need? There is a LOT of cabinet space in this place, plus the countertops.

The paint that is currently on there isn't very glossy at all โ€” semi-gloss at MOST. Do I need to sand everything or will a good primer work just fine?

Ugh. I almost want to give up on the whole thing, but I really hate the way it looks right now and we probably wouldn't have taken this house without the understanding that we would re-do the kitchen...plus all the work will pay off in the end, it will look beautiful, if only we can actually get it done.

Does anyone have tips? Thank you so much in advance.