Welcome!
Suggest finding a speaker you can audition before building and using a kit versus DIY design. Too many proud papa's become enamored by their "babies" whether they sound good or not, especially true for DIYers. Also recommend building a test mule cabinet if not using a kit to verify build-ability and if not woodworking savvy. Today's leading designs use controlled directivity (waveguides) but that takes very much R&D so don't expect state of the art results from DIY or even kits.
Also consider the total cost of going DIY versus buying assembled or even used as well as the quality of the completed speaker. Part of that total cost is resale (very poor for DIY, especially non-kit pieces). One of my favorite inexpensive speakers is the JBL 305 Mk 2: $300/pair; active (power amps built-in); can be used desktop or to fill a medium sized room; analog inputs; dynamic; detailed; and musical.
Start out by deciding what type of speaker you want. 2-way stand-mount/desktop, 3-way tower, dipole/open baffle, budget, domestic (spousal/neighbor) approval, what room will be used (big, odd shaped, shared, compromised setup, ability to add room treatments/subwoofers). Most audiophiles over gear for the given room constraints to satisfy their hunter/trophy collector urges and end up shopping more with their eyes than their ears (fancy thick faceplates or lavish veneers).
When shopping for speakers bring a good sampling of your favorite music and a notepad (forces you to critically listen). Limit yourself to 3 or 4 pieces per day (same ancillaries/room) to give a fair comparison and limit listeners fatigue. Ideally audition in your chosen listening space. Pick room first, then speakers to fit the space, then amplification to serve the speakers.
Recommend Floyd Toole's "Sound Reproduction" 3rd edition as the consummate audiophile primer to learn how speakers behave in-room, which will point you towards stand-mounts plus multiple subs. Toole is a respected authority.
