We are assuming that you are working with a fairly standard tower case. If you are building in a case with an unusual form factor, preparation steps may be different.
Remove Both Side Panels
The first thing to do is take both side panels off of the case (some cases might only have one, but rarely). Many modern cases use thumb screws to hold the panels in place, but some may just use standard crosshead fixing screws. In either case, they will be along the edge at the back. Even with cases that use thumb screws, you might need to use a screwdriver when loosening them initially.
As you look at the front of the case, the left-hand panel is usually the main access panel, with the right-hand panel giving access to some fixing screws and the cable management space in the case. Cable management is an important part of any build, and will be discussed in detail later. Generally, the only cases which don’t follow this format are Micro ITX and frame-mounted cases.
As you can see, the Thermaltake case we are using for our build also has some extra features behind the slightly expanded right-hand panel. As well as the expanded panel giving more cable space, there are also two positionable SSD cradles hidden back there. During the build process, it is usually a good idea to leave the right-hand panel off of the case.
Route the Case Cables
Before you fit a PSU and all its cables, there will already be several small cables inside the case, leading from the front header for the power/reset button, the front USB ports, etc. Check your motherboard to see where the front panel header connections are (usually they will be along the bottom edge of the motherboard when it is in position), and route the cables from the front panel accordingly. It is usually easier to do this now, than to do it when everything is fitted into the case.
Remove Unwanted Parts
Depending on the case you are using for your build, you might also be able to move/remove the optical drive racks and the hard drive racks (which are usually at the front of the case). Removing unwanted racks can help to increase airflow, or just give more room for large components. Not all cases will allow this, and will have the drive cradles riveted in place.
Fit Extra or Move Existing Fans
Most cases come with at least two fans pre-installed, one behind the front panel to suck air in and one at the back to expel warm air. Almost every modern case will be capable of having more fans. If you have bought additional case fans, now is a good time to fit them. To fit an additional front fan, you will normally need to remove the front panel.
This is normally held in place with simple plastic split pegs, and a firm pull will remove it. Be aware that your case will have wiring running from the front header (the power switch, etc.,) so don’t pull too hard. If an additional front fan can be fitted, you will see standardised fixing points (normally for both 120mm and 140mm case fans). Use the supplied fan screws to fit it, ensuring that it is installed correctly to pull or push air, depending where you are fitting it.
Install the Motherboard Risers/Spacers
The final part of preparing the case is to fit or move the motherboard risers/spacers (also known as Standoffs) to the correct locations. These double-threaded pegs hold the motherboard off of the surface of the case (to avoid shorting the board out) and are essential. Many cases are marked to show their positions for different motherboard sizes (ATX, mATX, etc.)