How do I populate cells (with formulas) from one google sheet into another while using one as a search key for the other? If C=This, State D

I'd like to populate Columns C and D in an entirely new spreadsheet, where Column D still auto-populates the cells just as it does in the original/first sheet (as it does in the photo attached inside this link)

I've tried the formula

 =IMPORTRANGE("1jD9MgFRnIi-44GaqsS5XAdhcV-Vg36eXnAXzkFh5xnM","'Form Responses 1'!C2:C")

in the new spreadsheet and it populates C, however, I only want it to show D IF/WHEN someone types their Username (from C in the original sheet) into Cell B3 in the new sheet (see image 2) ... If that makes sense.

P.s. I also only want two rows and two cells in the "new spreadsheet" (also see image 2). One Column for the search box (cell B3) where they type their username, and the other for the content in D (cell C3) that corresponds to that username in C.

i.e. D is autofilled when C is typed in