How to quickly reference the data of specified cells in other Exscl files in Exscl?

Enter or copy and paste the following formulas in C2 and D2, respectively.

= Indirect (B2&; "! A 1”)

= Indirect (B2&; "! C 1”)

= Indirect (""& b2 & A 1”)

= Indirect (""& b2 & C 1”)

Select "C2:D2" and then drop down to fill in.