@lynnewisconsin
Open both workbooks.
Activate the cell where you want the formula.
Press =
Switch to the other workbook, for example by pressing Ctrl+F6 one or more times.
Activate the worksheet with the cell you want to link to, then click on that cell.
Press Ctrl+Enter to confirm the formula.
You should see a formula similar to
='[Other Workbook.xlsx]Other Sheet'!$D$2
Now switch to the other workbook again and close it (saving changes if necessary).
Excel will automatically add the full path of that workbook to the formula.
It will look similar to
='C:\MyFolder\MySubfolder\[Other Workbook.xlsx]Other Sheet'!$D$2
Finally, save the workbook with the formula.
P.S. You can also type in the formula, following the pattern of the previous example. But it's much easier to point to the workbook, worksheet and cell.
