So you have what is known as a usb pass-thru. Basically an ecig on a string
These are good, I use one myself in the car to keep from having to change batts on a long road trip.
The plastic resevoir you fill up, is it filled with a cotton like material or do you pull a cap off the bottom, fill it and plug it back in?
Either way these are not compatible with cinnamon as for reasons beyond my chemistry background cinnamon turns this stuff in to goo over time which messes all sorts of things up.
You will need one of two things depending on the answer given to the above questions.
1 if you have a plastic round resevoir with cotton like material that soaks up the juice - you are using a cartridge and that is the standard from that era.
2 if you are using a whistle shaped resevoir with a removable cap at the non-mouthpiece end then you are using an ego style tank.
Cartriges are difficult to use, require some fiddling and don't last very long. Recommendation in this case buy a cartomizer. These bad boys are cotton filled devices that both hold your juice and act as a heating element all in one. They run $1-$3 each and will last 3 days to 2 weeks depending on how you use it and what kind of juice you fill it with. Then you'll need a drip tip. The drip tip goes in to the end of the cartomizer and gives your lips a place to go that looks stylish and isn't going to heat up and burn you... you know that last drag you would take when you knew you shouldn't and got burning filter and a red mark... let's avoid this.
If you have an ego style tank... they don't like cinnamon (no body told me this when I bought mine) but I have enjoyed a few b style ego tanks in my day.
These are just my opinions and the path I took to e-cig nirvana. There are so many options. I suggest searching around and looking at this section of the forum to absorb the wisdom of all who post. There are great primers and reviews... even a few great guides that can teach you about the equipment you have. Look for a local vendor and see if you can stop in to a physical shop.