No worries. I didn't know any of that stuff until recently either.
There's a sticker and online code that comes with each character. The sticker is for a poster to mark off which ones you have. The code is so you can play with the Skylander on your computer online. My husband said he still has the codes so I can get those. The character can be re-set. The first time you put the character on the portal you can go into the settings for the character and clear any old data. This also changes ownership to the new player.