Click the 'Clients' section (at the top), and then 'New client'
Fill in the details and click 'Create client'
(If this is a returning customer, you select him in the customer list, and create a new product, or a new repair, depending on if he has brought this product in before)
Fill in the details and click button 'Create'
Fill in the details and click button 'Create repair'
You can add comments, for example if the customer calls you asking for more to be done