Setting start and end dates from calendar

I’m having difficulty selecting the date range using the Calendar. When I select a day I would like to set the client tags as follows:

rangeStart = 2020-06-18 00:00:00
rangeEnd = 2020-06-18 23:59:59

What’s the correct way to do this?

(I’m doing this on an Ignition 7.8 machine …)

Something like this (untested) assuming only one Calendar object named Calendar. Not sure of the exact syntax in 7.8

rangeStart ="Calendar").date,0,0,0)
rangeEnd ="Calendar").date,1),23,59,59)