use a forstner bit if you have one of buy just the bit itself for the diameter size of your required tubing. Hard to say what your best option is to plumb it without seeing your stand and available space. if you can, place the pump at the input of your sump and run the plumbing up and out with you flex hose. Then you need to find room to place your skimmer. If it needs to be higher, for space limitations, you can just run the return over the lip of the sump then straight down. If it is on the same level, you need to drill it, it's acrylic right? Hope so... much easier, never drilled glass before. Then you need to buy the appropriate bulkhead to fit into your newly drilled hole. Remember that you will be drilling for bulkhead size not necessarily for you PVC
size, depending on the bulkhead. Now if your skimmer ends up elevated, which is fine, it will need a much bigger pump than the powerhead you have. It looks like a good size skimmer, a bigger pump would be nice. Check it's recommended flow capacity.