Search for "SX2110G-UW308 specifications" and found this link:
It shows there are 2 expansion slots and 6 USB 2.0 ports available on this desktop PC (2 on the front, 4 in the back), it also shows that the Operating System is Windows 8. This desktop does not have wireless, so you are correct, you have to add wireless to this system.
If you have never opened up a PC then I recommend a USB wireless adapter that has a plug and play compatible with Windows 8 feature. They are inexpensive and you plug it in to any USB port and it will automatically install. You don't even have to shut down the computer. Click here for a list of USB wireless adapters. Read the reviews and select one that has a mainly positive reviews: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100010074%20600028008&IsNodeId=1&Description=wireless%20usb%20adapter&name=WPA2&Order=REVIEWS&Pagesize=20
Lots of choices. Choose one that supports WPA2 security, has a good range. Antennas will give you a better range, and stronger signal.
- One (1) PCI Express x16 slot
- One (1) PCI Express x1 slot
If you are comfortable opening up the case, then go ahead, before you buy a card, shut down, turn off the power, unplug the system, open the case and look for the PCI slots. There should be two of them. Make sure they are empty and available. See if there is an opening in the case next to the expansion slot for the wireless antennae to protrude out the back of the case. There are lots of PCI express wireless choices. Pick a card with WPA2 security, it should say plug and play with windows 8 as one of its features, pick one with good reviews and a good range: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100010074%20600028008%20600014297&IsNodeId=1&Description=wireless%20pci%20express&name=PCI%20Express&Order=REVIEWS&Pagesize=20
Before you touch anything inside the case, double check that it is unplugged, touch the the case a few times to discharge any static, or wear a static discharge wrist strap. Plug in the PCI card firmly but gently, make sure it seats, make sure all the pins line up. Don't bend or break anything. Remove the metal or plastic slot cover on the case, close the case, plug it in, power on. It will also automatically install.