How do I add items to a list?

I'm creating a patch that at a certain part sends out numbers based on using an integer number (so you can drag it up and down to change it). I want these numbers to be added to a list. I want the list to get longer as the integer changes.

For example if someone scrolls through the numbers 30,31,32,33 then I want the list to contain 30,31,32,33. If someone then types the number 40, I want the list to then be 30,31,32,33,40. I don't think(?) I care about the order. I also want to be able to clear the list by sending it a message.

How do I go about doing this? I can't tell what object to use.