How can I attach an Excel sheet to a page, so that I can use an Excel macro?

Drag and drop the excel in edit mode, then insert-->Office Excel (or just write "{Office" to get a list of macros)

Note: If you dont drag and drop the excel (or insert the file), you wont be able to see it in the dropdown menu. 

If you want to see multiple sheets in a page, and edit the file inside confluence  itself you can use Excellentable

Hi @Samantha Sharkov 

When you are in the edit mode, you can just drag and drop your excel sheet.

Then you can type "/excel" and the excel macro should show up:

There you can select the "File Name" and "Page Name". 

Hope this helped.

Regards, Dominic