Fill in the parameters.

Create Wheel (not Pinion): You can either create the wheel or the pinion gear, not both at once. Re-run the create to create the other. 

Number of Wheel Teeth: The number of teeth for the wheel.

Number of Pinion Teeth: The number of teeth for the pinion. 

Module: The gear's module.

Shaft Angle: This would be 90 degrees for bevel gears that are perpendicular.

Face Width: The width of the teeth.

Root Clearance Per Module: The gap between the tip of the tooth of one gear to the bottom of the dedendum of the other, see app screenshot

Involute Clearance Per Module: The gap shaved off the involute surface of the gear, see app screenshot

Profile Shift Coefficient: The shift in the contact point of the gears, see app screenshot.

Hub Hole Radius: The hole radius in the hub.

Max Dedendum to Back Width: The maximum distance between the bottom of the dedendum and the back face of the gear, see app screenshot.

Shaft Radius: The radius of the shaft holding the gear.

Shaft Length: The Length of the shaft holding the gear.

Number of Spline Points: The number of spline points used to create the involute

Install:

The installer that ran when you downloaded this app/plug-in from Autodesk App Store has already installed the app/plug-in.

OR, simply double-click the MSI to install the app.

Uninstall:

You can unload the add-in without uninstalling it by clicking the "Stop" button when the add-in is selected in the list box on the "Add-Ins" tab of the "Scripts and Add-Ins" dialog.

Unchecking "Run on Startup" causes the add-in not to be loaded in future sessions of Autodesk® Fusion 360™.

To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer, and select the "Uninstall" button.

OR, you can uninstall it from 'Control Panel\Programs\Programs and Features' (Windows 10/11), just as you would uninstall any other application from your system.