How to disable keys at opening the spreadsheet?

Hi! I faced a problem with my VBA worksheet.

I have some data that needs to be updated by other users, but I have to ensure that no data is mistakenly erased. Therefore, I thought of disabling the delete and backspace keys.
However, the macro works only when I run it using F8 and cannot find a way to run it at opening the whole spreadsheet.

I tried writing the code immediately after starting the script. Then I thought of calling another macro, but it does not work, either. Currently, the code looks like this:

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Next thing to say is that I am a real novice to VBA and really count on someone's help!