Cannot get the column specific timestamp to display on checkbox

I have set up a Google sheet for attendance of Employees on which clicking on the checkbox, the current time is recorded.

I cannot get the specific timestamp in the respective columns when the checkbox is ticked.

Clicking on a different checkbox also change the timestamp for previously checked checkboxes.

I have used this formula here : =If(B2 = TRUE,now(),"") and used filter handle to apply the formula for other rows underneath.

I have used this formula: =If(B2 = TRUE,now(),"") The sheet can be seen here: https://docs.google.com/spreadsheets/d/1p6jmnHXtCu2m7BdLfC-23A51MrwkJJJpXidpbsDwxfU/edit?usp=sharing

I want to record the current timestamp, for each row. i.e on clicking of the checkbox the current time should be changed/recorded only for the column in the same row and not for other records.