Your personal information should include information about yourself (your name, a personal profile picture, your personal e-mail address, etc) as a representative of your brand. The brand information should include the public information of your brand (brand logo, contact information, aliases, etc). This allows influencers to get to know your brand better and you act as a point-of-contact.
You can edit both sections by clicking on your name next to your avatar in the left menu. Click My Account in the dropdown menu and click on the respective link associated with the information you want to update.