Charging rates (what you charge your customer) let you setup a "List" or rates that can be connected to your fieldworkers.
If they track time on a job you can optionally let the system create a cost for that job based on the time they have spent which will use the charging rate for the particular fieldworker on the job.
Select the 'Settings' icon in the left hand menu bar and select 'Billing'.
From here, you can see that you have a default rate which can have a description and cost per hour.
By selecting the + sign to the right of this rate will allow you to add a further rate. For example, Standard Rate, Out of Hours, Discounted etc.
Setting Chargeable Time Increments
Your business may charge by the hour or part hour; in which case, you can set up the increments by which your field workers time is charged.
In the same screen, (Select the 'Settings' icon in the left hand menu bar and select 'Billing'), under the Payment Terms you can adjust the time increments in which you wish to bill (in minutes):
Don't forget to select 'Save' before you move away from the page.
How to assign a charging rate to a staff member
From within settings > Staff members you can choose the charging rate for each of your fieldworkers. Scroll down to Staff rates and use the "Standard rate" dropdown to choose the charging rate and then press Save.