Why won't my memory card work on my camera?

It's a nikon l120 and I just got it today and I got a memory card as well it's an 8gb SanDisk sdhc card and I took 20 pictures and it said the cameras memory was full but why didn't it use the memory card? The memory card was in at the time and I just purchased it today so why didn't it work? And btw I'm not really that good with technology

Why didn't you read your manual?

The first thing you need to do once you have fresh batteries installed, is to format the memory card using the format feature on your cameras menu

Formatting the card in the camera will assure that it is fully functional and hopefully will not corrupt

According to your Manual, your camera has 102MB of internal memory and when there's no memory card inserted, images you take are saved to it. However, when you insert a memory card, images are automatically saved to the card.

So, are you sure that you're not actually looking in the camera's internal memory instead of the memory card?

p.s.did you remember to format your memory card in-camera before you used it the first time? If not, make sure there are no images on it. If there are… First transfer them to your computer, then format the memory card via the camera Menu. Reformat the memory card again after every upload.So, shoot, transfer (and back up) then format the card to delete All files from it, ready for your next shoot.