Auto-populating a spreadsheet

yes,

Are you referring to different worksheets in a single workbook, or different workbooks -- spreadsheets is kinda open to interpretation.

can you upload an example?

attached is how i would do that,

basically, you can use a pivot to do this (i sound like a broken record today!)

See the attached. I added a combined name column to your data.

Your dates are on the sheet2 area, two ways to go about this (one using combined name column, the other not).

--edit--

really, any approach will run into issues when you have last name, first name only. What if you have lots of employees with the same name (both first and last names)?

I would suggest you use a unique ID on each row, like an employee number, to prevent this issue.

Fine, we'll do it your way See attached.

Basic formula is here, this is what is bringing back the date values (repeated names would still lead to a problem).
=SUMPRODUCT(('Report Data'!$A$3:$A$17='Training matrix'!$A4)*('Report Data'!$B$3:$B$17='Training matrix'!$B4)*('Report Data'!$C$3:$C$17='Training matrix'!C$3)*('Report Data'!$D$3:$D$17))

Also, use conditional formatting to not show the 1/0/1900 date -- when you format a cell for dates, zeros become that fictional date. Recall 1 = 1/1/1900, 2 = 1/2/1900...