Dock Help

I'm trying to find out how to change the Dock on my iPhone 4.

I understand SSH'ing to some degree. . . I'm using Cyberduck and have been having good success so far. I'm new to this stuff.

I have downloaded the Future Dock and would like to SSH in and replace it.

Can anyone explain how to do this?

Also on a side note, How do you change an icon image to a different one using SSH?

Thank You

 

Ok, I figured out the icons but i'm still having a problem with the dock.
I understand now were to put the new dock but the issue i'm having is that when i put the new dock into the theme i'm editing it doesn't show up on my phone after the respring. but, if i take that same dock .png and add the @2x in the title the dock will show up after respring but it is very SMALL and centered.

Why will it show when i shrink it?

Please help i'm going crazy with this!! LOL