Using keywords is how you get your commands to include other objects in the game world. For instance, if you are standing in a room that has a bale of hay in it, and you want to pick that up, you can input GET HAY or GET BALE.
What if there are two cedar benches, and someone sits on the first cedar bench, and you want to sit on the second one? If you input SIT CEDAR, you will end up on the first bench. In this case, you will want to SIT OTHER CEDAR or SIT SECOND CEDAR. If you wanted to sit on a theoretical fifth cedar bench, you could SIT FIFTH CEDAR.
But now let's say that there are several cedar benches, several stone benches, and also five cedar chairs in the room. It gets more complicated if you just want to sit on the second cedar bench! Here, you can use multiple keywords and separate them with a period(.). You can use as many keywords as you like in this fashion. SIT SECOND CEDAR.BENCH will get you to sit on the second cedar bench specifically.
You might get confused at some point about what exactly the order of these keywords are. How do you even know which is the first or second cedar bench? Here's where the KEYWORD command comes in handy.
keyword <your keyword string>
At any time, you can use this to return the order of game objects in the area that match your keyword string.