The best place to find official documentation is the Acer Support website:
2 x SATA III 6Gb/s connectors (commonly used for SSDs), 2 x SATA II 3Gb/s connectors. Audio: Realtek ALC662 5.1-channel High Definition Audio. LAN: Realtek RTL8111E Gigabit Ethernet Controller. USB: 2 x USB 3.0 ports, 6-8 x USB 2.0 ports. acer h81h3am v10 manual
If you want, I can:
This is the most common stumbling block for OEM motherboards. The pinout for the Acer H81H3-AM is not standard, but a verified configuration exists for the F_PANEL header. The best place to find official documentation is
If you are replacing or repairing an Acer Veriton M2631G, understanding the front panel headers is crucial. USB: 2 x USB 3
Align the triangle on the CPU with the triangle on the socket. Place the CPU gently and lock the lever. Memory (RAM) Configuration Insert DDR3 memory modules into the two DIMM slots.
Search the motherboard model plus “manual” and “drivers” on the manufacturer or OEM support site. Use the exact model string “H81H3AM V1.0” to find the correct BIOS and driver packages.