Summarize:

A HomeGroup is a collection of Windows computers on a network, and is designed to make sharing files and printers between them easier than a traditional network. Only Windows 7 and 8 computers can join a HomeGroup.  Open the Charms menu. You can access this by swiping in from the right side of the screen with your finger or by moving your mouse to the lower-right corner of the screen. Tap or click "Settings". This option has a Gear icon. Tap or click "Change PC settings". This is is located at the bottom of the menu. Tap or click "Network" Tap or click "HomeGroup" Enter in the HomeGroup password and then tap or click "Join". The creator of the HomeGroup can find the password on his or her HomeGroup menu. If there is no HomeGroup detected, then you may not be properly connected to the network. Once you are connected to the HomeGroup, you can print to the shared printer without having to actually install the printer. The PC that is sharing the printer must be turned on to print.
Open the HomeGroup menu. Join the existing HomeGroup. Print to the shared printer.