Reply to Dicer & Midifighter inspired controller (Joypad PCB) NEED HELP!

I decided to try building an arcade button controller for turntables. I was browsing alot of DJTT and arcade cabinet community s for this and got comfident that i could really build this.
I wanted to build 2 of these using only one USB port, so decided to try this one and just hope it's easily hackable:
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT
Arcade buttons for the first prototype i ordered from Dealextreme.com where they were only 1 dollar each including shipping (bulk):
http://www.dealextreme.com/details.dx/sku.37487

Today i finally received my parts, but now I also need some help where to solder. I have pics included and I believe that the Joypad has a common ground. Am i right? There seems to be easily pointed solder points aswell, those silver dots next to buttons.

So do I solder one point of the button to the "button solder point" on PCB and other point to ground? Is it really that simple? I've marked the solder points with red dots and ground(s) with blue line. Those trigger PCB's are useless for me since I will only need 6 buttons / controller.

The controller will be the same width as SL1200 on battle position, so I can use it on front of my turntables, OR on each side of the mixer. So length (depth) will be 35cm and width 6cm. I will make the case out of plywood and cover from acrylic. I have all the needed materials for the case at work.

4 buttons will be for CUE points and 2 extra points are for sync and effect (maybe, I haven't decided yet).

Total costs so far are: buttons 10USD, controller 10USD. So this will be super cheap!
Parts:

PCB with solder points(?) marked with reds and blues are ground(?):


Button:


Thanks in advance for everyone who's willing to help me out.