This is your chance to really customize all your landings pages, emails, and campaigns. You have the option, which you should definitely exercise, to set you logo picture. We recommend a logo picture about 220x130 pixels. It’s not a big deal if your standard logo is larger, but just be aware that it will automatically be resized to scale.
You probably have a color associated with your brand. You can set the color by hex code or you can try eyeing if you click within the color box to have a color selector appear.