I don't know how these work. I've edited them but they don't take affect when searching. Any help anyone?

You can find an answer in the link below, whether you can understand and use it is another question.

 

Yeah I think I got it. It's just very sensitive,,still don't understand the significance of the weight though. It seems to alter the overall ability potentially massively, why is that? cheers

I think it is just for scouting purposes and helping to choose the right player for the right position.  This is just my take on the function.