Recently I have my admin password leak to my staff members and so they have been abla to change prices and stock quantites, including adding users. I want to know who did what and at what time, If could get an activity report that can give such info please.
Thanks again for assisting
It does not log that information. Even if it did,
It would just show that Admin did it 
You might invest in some cameras and secure your password better.
You can set up some reporting on SQL Server for that sort of thing. Google SQL Express Reporting and you should see some resources on how to do that. It may not show you who did it but it could show changes done to the database and times. This is not a SambaPOS feature so you wont get support on that from here but there is a ton of resources online about it.