Once you've set up a variable compensation type in the Settings section of the Hiring app, you can add this during the hiring flow.
As an admin
In the Offer Details step of the Hiring flow, you'll see the option to Add Variable Compensation next to Additional Earnings.
You'll then select from the Earnings Name drop down. These options are populated from the Variable Compensation types you created in the Settings tab of the Hiring app.
Based on the selections made when the variable compensation type was set up, you'll either enter the flat amount or a percentage for the worker.
Once you Submit the variable compensation, you'll continue with completing the rest of the Hiring flow as usual. If you are used an "Other" category of Variable Compensation, make sure that there is a corresponding Pay Type in Zenefits Payroll.