I'm currently building my first guitar from one of those kits you can buy from various places on the net. I've got to the stage where I'm planning the wiring but I've never done any wiring or soldering of any sort before and am unsure how to ground it all properly. I have attached the diagram that came with the kit. On the diagram it says to solder all of the the ground wires together, so does that mean I just take all 8 of the wires where it says "GND" and solder them all together? If so, do I have to solder them to something or just tape them up?

Thanks very much in advance,

The usual procedure is to choose one place to collect all the grounds together and solder them all there - very often the back of one of the pots.

In the case of the VVTT configuration there is very often a ground wire connecting each of the backs of the pots together.  Any other grounds can then be connected to the back of any of the pots.  This image shows it quite well, although for some reason they seem to have omitted the capacitors.  The yellow and orange wires are the grounds.