No need to scrap anything, but breaking things up into more manageable tasks, with natural checkpoints before you move on to the next task, makes it much more likely that you end up with a good final “product”. For your first DIY build, I’d suggest:
- Using your schematics, build the circuit on a breadboard and make sure things work as expected. Tweak things until if does.
- Revise your schematics, as necessary. Design a PCB, using through-hole footprints, and order the minimal set of boards from JLCPCB or other cheap “prototype” fab.
- If you feel confident in your soldering skills, you can use (reasonably sized) surface-mount footprints instead, but through-hole is a bit more forgiving (at least as long as someone else drills the holes for you; if you etch your own PCBs the equation is different).
- Populate one board, and test it. There may be mistakes. Find them and figure how to fix them.
- (Stretch) Fix any issues in the PCB layout (and/or the schematics), order another set of PCBs, and build a “production quality” board. Or three.
- (Stretch) Design another PCB, with surface-mount footprints. Consider having the fab add some components so you don’t have to.
Once you get more confident, you can skip some of the steps when you move on to other synthesizer modules…