Hello guys!

I don't know if my title is clear but let me introduce my problem:

I'd like to know how to do this :

"performance1" (with the 1 at the top of the word)

At the end of the same sheet :
1: the performance is calculated from the ratio between...

I think it's not difficult it's like a hypertext link but I don't know the step to do this..

Thanks if you can help me

It's not clear whether you're referring to a Table of Contents (which usually goes near the start of the document) or an Index (which usually goes near the end of the document). By default, a Table of Contents links to the content it references. An Index, however, cannot link to the content it references.

To implement a Table of Contents, the headings you want to appear there should have one of Word's Heading Styles applied. Creating the Table of Contents can then be as simple as going to References>Table of Contents and choosing a suitable format.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

I believe what you want is a Footnote (or an Endnote). Put the cursor after 'performance', and go to 'References' tab. There, either select 'Insert Footnote' or 'Insert Endnote'.