Classic Website Editor:
Go to the Website tab and click Manage
Click the Settings button in the upper right and then the Design tab on the left (make sure MVP Template is selected)
From there, click 'Home Promo Box 1, 2 or 3'.
Once open, you can edit the Label (the text that shows up), the Page (where the box is linked to), and also upload a new image.
Go to the Website tab and click Builder
Click the Site Settings menu at the top
Under the Design tab you will need to be using the MVP template
In the Pages list at the top select your Home page
Click on each box underneath your banner image and logo
Update your text and / or upload a new image