Hi Josh -
if I tell you, what do I get ? I like cookies and doughnuts.
click on System Preferences> Sharing on your computer with the G-Tech 8TB, and check FILE SHARING.
Three columns will appear. In the first column, hit the + sign, and select your G-Tech 8TB. In the second column (users) click +, and select NEW PERSON, and enter the name and password of the OTHER computer (the one that wants to share). Select it, and assign READ AND WRITE permissions in the 3rd column.
Select System Preferences> Network, and jot down the IPv4 address of this Mac.
Close all this.
Go to the other computer, and click on GO> Connect To Server, and enter the IP address that you just jotted down. Click on Connect. It will ask you for the name and password you just entered into the other computer. That's it - your drive is now available on this computer. If you don't see your drive on the desktop, click on Finder> Preferences, and check "connected servers".
Just remember, you CANNOT play HD video from both computers at the same time from this drive. This is a little "cheat" to get this to work - it's not shared storage. If you try to do full work (like a real shared storage system) you will crash your computers.