PC BIOS RAM Detection Fix

My brand-new build refuses to see all of its memory. The board is an ASRock Z890 Taichi and, although the system powers up, it immediately throws RAM-related beep codes and the BIOS reports no modules installed... (Budget: ₹600 - ₹1500 INR, Jobs: Computer Repair, Computer Support, Firmware Development, Performance Tuning, Technical Documentation, Technical Support, Troubleshooting, Video Conferencing)