A good video card can be a must when gaming. It is an easy upgrade for someone without much technology background. However, there are some things that you have to consider when choosing a card.
The first thing to consider is the BIOS/UEFI in the motherboard. Most newer video cards require UEFI in the motherboard instead of a standard/Legacy BIOS. You can find this information in the "System Information" app, in the BIOS Mode section, on your computer. The BIOS can't be upgraded to UEFI. There are three other important things to consider: 1) the length of the card; 2) the wattage required to run the card properly and 3) does the power supply unit (PSU) have any necessary 1x6-pin, 1x8-pin or both supplementary power connectors. If not, this will require a PSU upgrade.
You can determine if the card will fit by measuring the space where it will be installed from the Back I/O ports to the front of the case. There should be enough space to allow for good airflow. The airflow is extremely important because these newer high-power cards develop a lot of heat. HEAT is your enemy in a computer. The wattage required is very important, also. It is normally recommended that the PSU has 100W to 150W more than the card requires. This allows for extra power for peak needs and for other future upgrades.
Once these requirements are met you can choose the manufacturer that you like and find a card that will meet your needs. A good resource for assuring that you choose the best card for your system is the manufacturer's Tech Support. They are the experts on their products. I have always found them to be very helpful.
There are numerous videos online to help you with the actual installation.