In order to have Xpert-Timer recognize your phone calls and handle the correct projects, you need to let Xpert-Timer know how to react on each call coming in.
Open the client manager by pointing to "Windows" -> Clients.
Double click on a certain client to open the client data. In the tab "Address/Contacts" you can add a phone number you want Xpert-Timer to react to.
Then point to the tab "Telephony" and choose a telephone project to react on the number. You can use the button to create a new project or choose a project from the list by hitting the little "Search project" button.
If you have multiple contacts for one client, you have to manually activate the telephony module in each contact. This way multiple phone numbers could start the same project.
Now your CTI module should work.