When creating a prepayment from the backend or from an existing prepayment you can attach that prepayment to a specific layaway item or job. NOTE: You can NOT attach a legacy job or layaway deposit to a job or layaway. This link has info on how to convert your legacy job and layaway deposits into prepayments http://docs.bmjapp.help/en/articles/3151915-how-to-convert-a-legacy-job-or-layaway-deposit-into-a-prepayment
From the existing prepayment:
Click the edit icon to access the prepayment edit mode.
Click into the for field and search for the layaway or job you would like to attach the prepayment to.
Click the save icon to save your changes.
If creating a new prepayment from the backend
Fill out any of the prepayment info needed
Then click into the For field and search for your job or layaway you would like to attach the prepayment to
Select the job or layaway you want to attach the prepayment to then click the save icon.