In this screen, the yellow highlighted area, you can enter any parts you will use. Remember, if you add a part, the software will "Remember" this for you and have it available in the dropdown for you next time.

You may or may now choose a Vendor that supplied you the part. To add a vendor to your dropdown, please refer to the "Vendor Setup" page.

Now type the quantity of parts. For e.g. choose 4 for 4 spark plugs. Then type what you paid for and from the "Markup" dropdown, choose a percentage you want to markup or simply skip this part and type your own price. It is important to note that the software will use your own cost to calculate the profit. So it is important to type your own cost if you would like to be effective in cost control.