In Order to install it you need to run the setup the AX2012 Steup, in the Add Ins you will find the Addin for Office. The installation is really simple, just next next and finished.
Once done, open Excel 2013,
if you see the Dynamics AX Tab, its good(Then go to Step5), if not, do these steps:
Step1: File> Options as highlighted
Step2: Go to Add-Ins> Manage> Com Add Ins and Ok!
Step3: Select the Microsoft Dynamics AX Add-in for Microsoft Excel and click ok.
Step4: Now you will see the Dynamics AX Tab.
Step5: Open the Dynamics AX Tab and click on Options.
It will take some to open.
Step6: Now input the AX Server Host name.
Final picture will look like this in below screen shot,
and all the company details will be shown!