updated docs for timesheet

erpnext/docs/user/manual/en/projects/timesheet/index.txt

@@ -1,3 +1,4 @@
 salary-slip-from-timesheet
 sales-invoice-from-timesheet
-timesheet-against-production-order
+timesheet-against-production-order
+timer-in-timesheet

erpnext/docs/user/manual/en/projects/timesheet/timer-in-timesheet.md

@@ -0,0 +1,26 @@
+
+# Timer in Timesheet
+
+Timesheets can be tracked against Project and Tasks along with a Timer.
+
+<img class="screenshot" alt="Timer" src="{{docs_base_url}}/assets/img/project/timesheet/timesheet-timer.gif">
+
+#### Steps to start a Timer:
+
+- On clicking, **Start Timer**, a dialog pops up and starts the timer for already present activity for which checkbox `completed` is unchecked.
+
+<img class="screenshot" alt="Timer in Progress" src="{{docs_base_url}}/assets/img/project/timesheet/timesheet-timer-in-progress.png">
+
+- If no activities are present, fill up the activity details, i.e. activity type, expected hours or project in the dialog itself, on clicking **Start**, a new row is added into the Timesheet Details child table and timer begins.
+
+- On clicking, **Complete**, the `hours` and `to_time` fields are updated for that particular activity.
+
+<img class="screenshot" alt="Timer Completed" src="{{docs_base_url}}/assets/img/project/timesheet/timesheet-after-complete.png">
+
+- At any point of time, if the dialog is closed without completing the activity, on opening the dialog again, the timer resumes by calculating how much time has elapsed since `from_time` of the activity.
+
+- If any activities are already present in the Timesheet with completed unchecked, clicking on **Resume Timer** fetches the activity and starts its timer.
+
+- If the time exceeds the `expected_hours`, an alert box appears.
+
+<img class="screenshot" alt="Timer Exceeded" src="{{docs_base_url}}/assets/img/project/timesheet/timesheet-timer-alert.png">