If I understand you correctly, you click on 'Insert' from the menu, click on "Object...". Select the 'Create from File' tab and browse to the file you want to insert. Select 'Link to file', 'Display as icon' or both and hit 'OK'
If you are trying to insert an existing Excel worksheet into another Excel workbook, then open the original worksheet and the workbook where you want to insert it. Put the "new" (receiving) workbook in background and have the "source" worksheet open.
Right click the worksheet "name" tab at the the bottom of the worksheet and click "move or copy".
Then click the "make a copy" button, go to the list of active workbooks listed in the dialogue box above the "actions" list. Click on the workbook where you want to install the copied worksheet, including where in the workbook you want it installed ("before ...").
You are done. I suggested using the "make a copy" purely for safety. Both worksheets will be identical, so you can go back and delete the source worksheet if you do not have any other need for it. The "make a copy" action just assures that the source file will remain untouched and intact in case you do something stupid.
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