Concat Now Time in YYYYMMDDHH with LastName keyword test field as one string value

Here's how to reformat the date and time

https://support.smartbear.com/testcomplete/docs/reference/program-objects/aqdatetime/date-and-time-format-specifiers.html

If you want to use that in another instance of the test, then store it in a Project Variable or a Project Suite Variable. Otherwise it won't be stored for next time.