You will most likely want to change the colours of Bliss to match your brand. All of the colour settings for Bliss are within the stylesheet for easy swap out. You can find the colour codes in the comments at the top of the stylesheet.
To change your colours you can use this handy tool
Before making any edits to the theme, open the webpage linked to above and click on the ‘Choose file’ button, select the style.css file from the Bliss download package and then click on the ‘Load Data’ button.
You will then see this screen. Select your new colours to replace the existing colours and then click the ‘Generate’ button.
You will be given a new stylesheet with your own colours to download. Click the ‘Open CSS File’ button and copy the entire contents of that page to your clipboard.
You can then navigate to Appearance>Editor and in the style.css file replace the contents with the contents of your clipboard and save. Your site will now be in your chosen colours.
Alternatively you can right click and save the file and then upload it to your site via FTP.