Terrarium Circulation w/ Fan Q's???

[Tim]

I have had a terrarium set up before with a small fish tank but a lack of air circulation had some bad effects. I know about the little computer fans, but I could never find out how to convert them. I mean there's just the wires, and the adapter???? does that have a plug for an outlet? It'll probably be like obvious, but if anyone can explain the assembly of this I would greatly appreciate it...

Thanks, Tim