How to link separate Excel files to auto-populate cells

Just change the last entry from I_34 to I_3412

Formula:

=LET(Instructions, "Amend Workbook, Worksheet and Range, as required",  Mdata, 'C:\Test\[Example_Mastersheet.xlsx]Sheet1'!$A$1:$D$1000,

 MA, INDEX(Mdata,SEQUENCE(ROWS(Mdata)),1),  MB, INDEX(Mdata,SEQUENCE(ROWS(Mdata)),2),

 COut, IF($F2<>"",FILTER(Mdata,MA=$F2,FILTER(Mdata,MB=$G2,"no match")),

       IF($G2<>"",FILTER(Mdata,MB=$G2,"no match"),"no match")),

 I_34,IFERROR(INDEX(COut,,{3,4}),""),I_3412,IFERROR(INDEX(COut,,{3,4,1,2}),""),I_3412)