Keep adding kit to your case…
5 Memory
Study the manual to see which slots to use: this is most pertinent for dual-channel configurations. Note that memory is probably the most statically sensitive thing we’ll be handling. The modules can only be installed one way, and will hopefully click into place without struggle.
6 Graphics
Locate a PCIe x16 slot and remove the corresponding grills (many cards occupy two slots) from the back of the case. Larger cards can be hard to wrangle into place, and may obstruct subsequent drive installation. High/ mid-end GPUs require dedicated (sixor eight-pin) 12V power connections.
7 SATA drives
Your case may provide tool-less trays to house drives, but screws are more secure. 2.5-inch drives are secured from the bottom, where as 3.5-inch drives have side mountings. Use angled SATA connectors at the drive-end, and straight ones to plug into the motherboard.
8 Cable tidy
Install at least one fan if your case doesn’t have one. Some cases enable cables to be routed behind the board, to maintain tidiness. Stray cables can be bundled together and secured with cable ties, in a corner ideally. The idea is that air can flow freely around components. And we’re done!