I'm trying to copy a block of cells, but instead of shifting down the rest of the rows, it overwrites them
How do we copy and paste a set of cells and shift the rest so nothing is lost?
Instead of clicking "Paste", right-click or Ctrl click and select "Insert Copied Cells" or "Insert...", depending on your version of Excel.
This will give you an option to shift cells right or down.
If you cut cells, the context menu will have the option to "Insert Cut Cells" instead. Microsoft has a support article that describes these steps and other copy/paste options.
In the Mac Version it's: