Need to add a switch to expand the network ports

[Dilanjan]

Dear Team

I have a Cisco 3850 Switch in one of our offices, the network ports are running out at that site and I need to add another 3580 switch to expand the network, Could you please let me know how to do this.

Do both switches need to have same IOS version? and I am quite new to networking so please help me on this

Thanks in Advnace

Kind Regards,
Dilanjan

[Leo Laohoo]

Stacked switches needs to be in the same version. 

Stacked switches firmware needs to be in either Install Mode or Bundle Mode (not both).