Here is what you previously asked that I answered, "How to Use it is: Code the file. Then, you should make a backup of your QB file, because there is no unimport. Then you use File menu > Utilities, Import and there is the tool to browse to the file you made."

Maybe the emphasis helps?

Here is what you stated next: "However "File menu > Utilities, Import, IIF" don't have an option for importing "General Journal Entry".

And I pointed out you browse to your File. The File contains the Coding instructions. The Coding is 'as general journal" or "as invoices" or "as checks" or all of that can be in one import file.

Here are the pertinent instructions I already gave, found in the Instruction Kit, which you found, because you quoted it:

QuickBooks cannot import IIF files just by double-clicking the IIF icon or using a Windows context menu. IIF file import can only be initiated through the QuickBooks user interface (File > Utilities > Import). Some system administrators have found it convenient to associate the IIF extension with their IIF editor (usually a spreadsheet program). This way, double clicking the file quickly opens it in the editor of your choice

Exactly what I stated.

I recommend you work on one of the provided sample files. This is a programming function, so it helps to have some understanding of Coding.