You should be able to do it at the pump. Best to ask at the fuel island now before you need do buy it so you will know how.
Just go inside to activate the pump. They'll ask if you need anything else, (besides fuel,DEf, reefer), you say "yes, fuel conditioner". Theyll say "anti-gel?". You'll say, "yep, that stuff" Theyll walk you through it. They see n00bs come through there every day.
when it ask for oil or additives. it will ask what your card is set up for. if your company has the cupcake option on your card turned on. then you can add a cupcake to the fuel purchase.
I guess my confusion is, when I hit the additive button, so I go inside and get said additive? Is it being pumped through the fuel line, I feel dumber by the minute!
Go inside Fuel stops do nothing for you but make you fat on worthless garbage to shove down your neck.
Addendum: northern states will pretreat the fuel during colder months. Unless you expect EXTREME temperatures, you dont really *need* additives.
During winter I always fuel up at the end of every day. Diesel treatment if fuel is from southern states or if temps in the teens. Never set trailer brakes, they might freeze up overnight. Next time you're at the fuel pump, pay attention to all the questions on the screen. One should be "any additional items/additives?" something like that. Press yes, continue normal fueling routine, when you're done, walk inside and pick up items you need, take to the fuel desk and tell them to add those to the pump you just used. The cashier will scan items, and you will sign the little screen. Voilá! Just make sure you know what items you're allowed to buy. I have to pay out of pocket for windshield fluid. Can only buy oil, antifreeze and diesel treatment on my fuel card.