debug - Set this to 1 if you are facing an issue with the Power-Up. Then go to the browser's Developer Console to check out the log. I.e. debug=1
unit - If you want to change the unit of measure for the duration in list. Possible values are days, minutes and hours. I.e. unit=days
decimalplaces - Set this to the number of decimal places to show in the duration for each card. I.e. 0 means no decimal places will be shown: decimalplaces=0
badgecolor - Set this to the background color you want for the time badge. Set it to badgecolor=none if you want a transparent background. Possible values: blue, green, orange, red, yellow, purple, pink, sky, lime, light-gray
excludelists - Separate the lists names you want to exclude from computation by commas i.e. excludelists=TODO,DONE

When you start using any of these, the 14 day trial will start automatically. After the trial the premium features will cease to work. Go to the Power-Up menu and click Subscription to purchase a premium subscription if you need one.
colorranges - If you have set unit to days, you can do the following: colorranges=0-2 yellow,2-10 orange,10+ red
excludedays - Possible values are mon,tue,wed,thu,fri,sat,sun. For instance, to exclude weekeends do: excludedays=sat,sun
format - Format duration. Possible formats are dh and dhm. To display day, hours and minutes do: format=dhm
mode - Add additional badges to card like showing time until due date or showing duration since issue creating or displaying cumulative duration in certain lists. To add additional badges do: mode=duration on board,duration until or past due,cumulative

Reload the board page after you have clicked save for the settings to kick-in.