The customer screen (select the Sales button from the main screen of the application, then Customers) contains a number of useful options that may help speed up viewing all jobsites created for a specific customer, and from there, one can edit a jobsite, delete a jobsite or create a new job for the specific jobsite.
From Sales / Customers
Highlight (or filter) the customer you want to work with.
Click on the small "+" symbol to the left of the Customer.
This drops down all the jobsites for that customer .
You can select a specific job , by left clicking on that job one time.
This will bring up the Job History to the right hand side .
Right click on a jobsite and you will be able to edit the jobsite, remove it (if there are no jobs associated with it), edit ot or add new jobs for it.