I've also had some other difficulties with my first build.
3 out of the 4 fasteners for the heatsink can be secured but I'm having troubles with locking the last one in. I repeatedly tried removing it and putting it on again but 1 or 2 would always not fully fasten.
My friend and I tried building it with a plastic mat over carpet, was that okay? We occasionally grounded ourselves by touching a nearby mini fridge, I dunno if that worked but we couldn't connect the power supply to the wall to ground ourselves with the case.