Dumb question

Ok, I've been driving several different trucks the past few years. The other day I was put on a "super 10." I know how to shift up (i've always floated gears) but how the heck do you downshift that thing?? Ya know........that button on the side that shifts so well going up, but how is the down lol!

 

Thank you D Mann. One of the trucks with the S 10 is easy to shift, the other one is a pain due to it just being shot. It had no brakes to speak of, I had only been in the other one to deliver a load a mile away so no time to really get used to anything on it. I'll only be on one of them for short hauls once a week or less hopefully it'll be easier this time. I just hate being on a different truck all the time. One 18 wheeler has a good transmission, the other one should be blown up, the S-10s are dump trucks, then cement mixers etc. and..................well, then there's the other trucks so without much in the way of instructions I've been just winging most of it. I'm keeping my fingers crossed that they dont ever put me on one of the trucks with 2 stick shifts.