PCI slots on the motherboard are used to connect a wide variety of devices, from video cards and sound cards to modems and USB hubs. Installing a PCI card into the slot is not difficult, the whole process will take a couple of minutes. Read this article if you want to know how to install a card in a PCI slot.
Steps

Step 1. Disconnect the computer from the electrical outlet
Turn it off and disconnect it - in other words, disconnect the system unit from electricity by pulling out the appropriate cable. However, then you will need to disconnect all other cables that are connected to the system unit. If you have used the computer recently, it makes sense to wait a few minutes until it cools down.
Note: other PCI cards require pre-installation of drivers on the device, which is rare these days. Nevertheless, you still need to look into the documentation for the PCI card

Step 2. Open the computer case
PCI slots are located on the motherboard, and there is only one way to get to it: by opening the case of the system unit. To do this, you will have to remove the side cover (the right one, if you look at the back panel of the case), which, as a rule, sits on screws (sometimes there are case models where you first need to remove the top, but everything is also on the screws).
- As a rule, you do not need a screwdriver to loosen those screws, although occasionally you still cannot do without it.
- Do not place the cabinet on carpet or similar surfaces. Static electricity created by friction will kill boards quickly, unnoticed, and at times.

Step 3. Find PCI slots
Rectangular slots opposite rectangular holes (covered with plugs) on the case are just what you need. Most likely, one or even 2 PCI slots (those closest to the processor) will be occupied by the video card. There will be, respectively, 1-2 slots free, unless you already have some other boards installed.
If you can't find PCI slots, take the manual for the motherboard, everything will be written there

Step 4. Remove the cover opposite the empty PCI slot
The place opposite each slot is covered with a cover so that no dust gets into the case. Do not be afraid, nowadays you no longer need to break out the plugs, they, as a rule, are on the clamps, or even on a single clamp. The main thing at this stage is not to be mistaken with the stub.
Do not remove unnecessary plugs so that excess dust does not enter the case (and it is all there is unnecessary)

Step 5. Ground yourself
Remember what we said about statics? Remember: before you crawl into the inside of your computer, you need to ground yourself. If you do not ground, then there is a risk of killing the board by static.
An electrostatic wrist strap, available from a computer supply store, will work fine (you will need to put it on your wrist). However, you can ground yourself in another way - by touching something metal

Step 6. Take the board out of the box
Pull it out carefully, do not touch any contours etched on the board, or the contacts.

Step 7. Insert the card
So, place the card with the contacts on the PCI slot and push it down so that it goes into the slot. Use force wisely, don't break anything! Then be sure to check if the card is fully seated.
If space allows, then you do not need to insert cards close to each other. Leave an empty slot between them, so they will heat up less

Step 8. Secure the card
With the same fasteners that you removed to pull out the plug, now fix the card, but more reliably so that it does not wobble!
The map will be in a horizontal position, so the issue of anchoring is much more important than it might seem at first glance

Step 9. Close the computer case
Put the side panel back in place, don't forget the bolts. Then put the computer back and reconnect everything that you disconnected before. However, if you have connected a board that, say, adds new USB ports, then do not connect anything to them yet.

Step 10. Install the drivers on the new device
Turn on the computer, wait for the OS to finish loading. Perhaps you will have an OS with which you do not have to install drivers manually - everything will be recognized and installed automatically. If this happiness passed you by, then just insert the driver disc into your computer and install the drivers.
- Without drivers, a rare device will function correctly and fully.
- After installing the drivers, you will need to restart your computer.

Step 11. Connect devices to the board
If you've installed a USB hub, now is the time to connect additional devices to it. If we were talking about a sound card, then now you can connect headphones there, and if about a network card, then a modem.