Remove seconds from a timestamp field

If it is just for display purposes, you can select the individual column and go into the Modelling Tab on the top menu.  Under there is a Data format section whereby you can choose a format that does not display the seconds.

If you are wanting to strip out the seconds for the purpose of data comparisons, you will need to perform an operation that will 'round' the seconds.  This will depend how the data is stored, but generally time is the decimal component of the Date/Time number value.  So 0 equals midnight and 1 the following midnight, with 0.5 being mid day.  This would mean that a single minute would be (1 / 24 / 60) or (1 / 1440)

If you take the number you have, multiply it by 1440 and round to zero decimal places (integer), then divide that back by 1440 and store as a decimal, you will have rounded the number.

Consider how you round, as you will move the time either up or down to the nearest second.  If you want to always round down, you need to use a "Floor" operation instead.