This is a 9-pin block (actually 10-pin but one is keyed missing). Refer to this layout:
: Two DDR4 UDIMM slots supporting up to 32GB of unbuffered memory at speeds of 2133/2400 MHz. Expansion Slots : 1 x PCIe x16 slot for dedicated graphics cards. 2 x PCIe x1 slots for additional expansion. 1 x M.2 slot for WiFi/SSD (2230/2280 form factors). Storage : 4 x SATA 3.0 ports for HDDs or SSDs. ib250mh motherboard manual
The board follows a standard m-ATX layout (244mm x 200mm): This is a 9-pin block (actually 10-pin but
Use the F12 key during boot to access a temporary boot override menu without entering full BIOS settings. ib250mh motherboard manual