Hi Mariam,
If you want to split the date time components , you can try to use the On change Event of Date picker ,
There you can define a custom logic to do the parsing on the selected Date Time.
Also you can use the below functions on the save button activity depending on your requirements.
I would suggest to go through the following document for date time parsing and formatting :
https://docs.mendix.com/refguide/parse-and-format-date-function-calls/