The six keys in the middle are what you press to make the braille dots. You simultaneously hit a combination of those keys to make the dots for each braille cell. When you do, the carriage automatically advances to the next cell.
The dots in a braille cell are numbered from 1-6, starting in the upper left corner, going down, and then over to the upper right corner and moving down. They keys on the brailler start at the center, count out to the left, then return to the center and count right. In other words, a braille cell is numbered:
and the brailler keys:
The center key is the spacebar. The round key on the right is the backspace and the round key on the left moves you to the next line. The large button/lever above these keys is used to move the carriage back and forth. Paper feed rollers are on either side.
Unlike a printer or typewriter, the paper feeds in and then comes out the same place. You start by rolling the paper into the body of the brailler writer by turning the paper feed rollers. All the paper but the first line goes into the machine. Then, as you type and move down the page, the paper comes back out where it was fed in.
Just like a typewriter, it "dings" when you near the margin. The margins are set in the back of the machine.