There are dozens (hundreds?) of different ways to finish, so you’re going to get suggestions, and you’ll want to try a few and decide what you like.
Me personally I use tung oil. Get the 100% stuff, then mix it 50/50 with mineral spirits, paint it on, leave it for a bit, and rub off the extra - you’ll have the most beautiful matte coating that’s also waterproof. If you want it shiny, you can do additional coats, and even sand in between with really high (2000) grit sandpaper.
This is just 1 layer of tung oil on mahogany:
BTW, you upload pictures by either dragging/dropping them, or clicking on the icon that looks like a box with an arrow coming out of the top.