Welcome!
First, the term is "Do It Yourself" or DIY. If done right DIY can dollar-for-dollar match/exceed pre-manufactured gear (avoiding expensive machined faceplates for an example. And of course you can customize your piece (upgrade capacitor or veneer for instance).
Second, suggest starting out with kits. There are lots of good kits and advice out there. CSS has some of the best loudspeaker kits for beginning DIYers. Realize that a good assortment of quality tools will be needed to do good work.
Third, avoid designing anything. There are professionals out there, not pretenders or glorified hobbyists, who do that for the living and are part of organizations with deep R&D/manufacturing histories making stuff that DIYers simple can't match. Even adding No-Res is a crap shoot.
And above all, be wary of the "proud papa" syndrome where everything you do sounds good until it doesn't. In some circumstances DIY can out perform pre-manufactured gear, but only under extreme conditions (use of exotic/uber expensive parts/materials, ultimate workmanship, so delicate/big/heavy it can't practically be shipped, etc.).
