A really quick way to edit your guides is from the LibGuides Shortcuts box on your dashboard. This will display a list of all guides you have permission to edit, with guides you own listed first so you can more easily find them.
Not sure if you're on the dashboard? If you've logged into LibGuides, then this is usually the first page you see. However, to get there at any time, simply click on Home in the orange command bar.
Then, in the LibGuides Shortcuts box, use the Edit Existing Guide dropdown to select the guide you want to edit.
To see a list of all guides in your system, go to Content > Guides. Depending upon your user account's permissions, you will be able to view and edit guides from this list