In the top navigation click on the Actions link, then on the next page click the 'New Action' button.

In the pop-up, name your action Barometer, and describe what your action will do. In this case 'Check barometric pressure and adjust panel meter'

Here is how you will want to set up your action. Set to trigger the action any time the barometric pressure sensor receives data (every 15 minutes). Then, use the map block to convert the barometric pressure value (hPa) to a value the meter can use (PWM). Then round that value to a whole number and set the panel meter to that value.

Once you have your new Adafruit IO Action set up like above, click the Save and Run button. You should see your panel meter show the correct hPa value.