i agree, you need to define your goals and what you want out of the sump before you can really decide how to build it.. but basically if you can operate a tape measure or ruler reliably, and can operate a tube of toothpaste, you can probably do this.. basically you'll measure the inside of the tank your gonna use for the sump, call your glass supplier(i used a local glass shop) but home depot or michaels or hobby lobby can probably cut the glass for you as well... then get yourself a tube of aquarium silicone, and glue the glass sheets in...
now, when it comes down to figuring the math, the flow rates, where exactly to put the baffels in, how tall they need to be, and things like that, i'd be more than happy to help you figure that part out.. i've built a couple of them myself, and i've never had a flood from my sumps...
so, what are you wanting to gain by adding a sump? what filtration are you using now? and if you dont mind me asking, what is the timeline and budjet for this project... also, what does the bottom of your stand and or setup look like, how much space do you have for a sump?
heres a pic of my first sump/fuge...