Stacking N2000 Series

Hi All,

Actually I have bought 2 N2000 series and now I have bought another one. (So I have 3 now). 

I have the stacking cables.

My Question is :
- how do I stacking the 2 switch with 1 new switch? (Best Practice)

- Do I need to shutdown first the 2 switch to deploying stack cable?

- Is there any document to troubleshoot if I fail doing stack?

Please kindly need your help.

Thanks before,