Customizing what you want your customers to see in their portal can be done in Configurations > B2B Portal Settings.
TIP: If you want to view the portal from a customer's perspective, create a TEST customer and invite that test customer (best done with your own alternative email account and in INCOGNITO mode in your browser)
Choosing the attributes you want to show and those you want to hide can be done in "Attributes"
Managing your colors and photos can be done here, selecting the "custom" drop down. An image in the banner can also be added.
Content can be added to the B2B portal. You can add content to be shown to your customer in the "About Us" section and an announcement can be activated and deactivated at anytime.
Below is where the content will show on the B2B Customer facing portal with the content from the "About Us" Section:
The screen shot below shows what you will see in the announcement banner when you change the content and activate the banner: