Building a bay window from scratch.?

im sure your dad is already impressed with you.make your top and bottom plates.at least 3/4inches thick.shape the bay you like.cut both at the same time with a jig saw.so they will be identical in shape.install one to your plate piece.and the other to your header i recomend you screw them in.support the bottom from out side to prevent sagging from the weight of the gl.if th top is not under you over head cornis.you need to put a roof over the top.this gets very tricky.to prevent leaks.use flashing at the top connecting to the house.the roof could be metal or shingles.ask your dad to check this part of the job.or help you with just the roof and flashing.if this part of the job is not done correctly.you will have nothing but heart aches every time it rains.and you will have to hear your dad telling you.itold you you would screw it up.sealing the top is the most critical part of the job.then install you vertical pieces.clear 2by 6.or 2by 4s.determin the width of each opening.be sure they are plumb.(level)then your cross peices.they will have a dificult cut on them.cut on an angel to meet the vertical pieces.pre cut all moulding to hold the gl in. this should be installed as far out to the outside as possible to prevent water or snow from seeping in.because of the angle of the cuts.you will find the gl will have to be installed from the outside.use putty or silicon chalking to seal gl.this is also crittical.if you could afford thermo pane do it.singel gl will sweat with temp.changes.and that is annoying.well from here it looks pretty good.good luck.ask your dad to check you out now and then.he may rub you a little.but you dont want trouble in the future.