programmatically update project server 2013 timesheet

Hi

I've been tasked with writing an application (console app) that periodically gets data from our timesheet system and push those data into Ms Project Server 2013 timesheet for each individual user.

The service account that this console app will use will have administrator rights on Sharepoint and project Server.

So programmatically, how can I enter timesheet entries for each individual user?

Using CSOM? PSI?

Please provide example.

Thanks in advance

Alex