[quote=@nerminator]
I have a question, is it possible to use any characteristics as a skill? and if so, how?
[/quote]

I assume you mean if you where, for instance, in a running race, and so you would use your DEX.
When this happens we use DEX x 5.
But this can sometimes change, to x4, x3 and so on. Depending on how hard the skill check is. 
I think its best not to worry to much, I will tell you if you need to roll for something's and what you need to roll.