The ratio is simply the amount you have uploaded divided by the amount you have downloaded.
The minimum ratio requirements are explained (sort of) HERE
You have downloaded less than 5GB so you need a ratio of at least 0.25.
If you uploaded your own video of 2GB you haven't been given the full credit. But if you were helping to seed a torrent you would only get a credit for the amount you actually shared with other people.
You don't need to go 'full freeleech' yet (although it is useful if there is a movie there you want) as you have a buffer of nearly a GB before you reach your limit. Just take the downloading easy until you build a good ratio and keep an eye on your ratio as you go