If you have enabled cash management, you'll need to enter in your Default Float. Your default float is the available amount of cash you have on hand. Here is how you add or edit your amount. Note: This feature is currently only available on iOS.
On the main screen, tap the three horizontal lines in the top left corner (pictured below).
Once in the menu tap Settings (pictured below).
Tap Cash Management (pictured below).
From there scroll down to Default Float, add your new amount and enable Cash Management. Once done just tap Save (pictured below).
For more information on how to change your float amount via the Tappr App, please watch the below video.