You can define a payment schedule for your customers on the estimates that you send out.

After you enter the required information on a newly created estimate,  choose "Manage Payment Schedule".

Add the payment information that you need in the "Payment Schedule pop up. Choose "New Payment Line" to add a new scheduled payment to the schedule. Payment lines can be in a specific amount or in a percentage of the invoice. The remaining amount will display on the right hand side of the pop up. 

Add as many New Payment Lines as you need including the amount and choose "Set Payments". Optionally, you can enter a Due Date if that pertains to the terms of your estimate.

Your payment information will now be displayed on the estimate once you choose "Preview".