Once you have logged in,
Go to Settings > Branding on the left side panel
Click on Whitelabel link , so you can add your own branding.
This will bring up the same page again,
with logo and colour scheme panels which you can click on.
Click on the logo to upload your company logo -
Make sure it is the correct size as requested - 224px wide by 64px high.
Click on the Colour scheme on the right side of the logo -
Different options will appear in the popup.
Once you have chosen a Colour option -
You can preview this to see how it will look to your clients.
Click "preview screen in new tab" - too see a preview of the chosen theme.
Another page/popup will appear,
This is the "branding preview mode " showing your logo, and chosen theme
You can select different themes and preview again
Once you are happy with your previewed colour scheme - Click done
You can also specify your company URLS on the Branding page: