There are two colours in your branding preset; Background Colour and Text Colour.
To change the Colours, tap the 'Presets' button at the top right corner of the screen and tap the preset you want to edit.
Swipe through the row of icons in the middle and select the settings you want to edit.
Tap a colour swatch to edit the colour, then either swipe through and select from one colours in the predefined colour library, or tap to enter the HEX code of your brand colour.
A HEX code is a six-letter code prepended with a '#' symbol that represents a unique colour. For example: #0000FF is blue, #FF715B is orange, etc. If you don't know the HEX codes for your brand colours, your graphic designer will be able to give them to you.
