I download them and add them to the scripts folder, but nothing. Am I missing something? First time user, be easy ;)

Which scripts are these?

When you start the client, do you encounter an error? One of them may be broken. 

I download them and add them to the scripts folder, but nothing. Am I missing something? First time user, be easy

If you had the client open when you added the local scripts, press the "Refresh" button.

 

If the client was not open when you added them, it means one of the scripts are broken. Remove all the scripts and add them back one at a time until you figure out which one(s) is broken.

Are you downloading from the SDN? are you following the instructions provided by the scripters ? Make sure you refresh your script page after every download. 

I'm downloading from the local scripts, what is the difference between them and the SDN? Thanks for the quick replies

Make sure you aren't downloading broken ones.