Nighthawk Model MR 1100 Where do I find the network security key code

Netgear has set up a community forum specifically for the Mobile Router products. Most of the people who watch that forum are more likely to have experience with Mobile (AC, L and M series) routers. Might be more likely to find someone who has a solution if the question is posted there:
https://community.netgear.com/t5/Mobile-Routers-Hotspots-Modems/bd-p/aircard

Please use this link to the main forum product list to review and choose where to make your posts. 
https://community.netgear.com/t5/NETGEAR-Forum/ct-p/en-netgear

Thank you

You can go to the support site at: 

MR1100 | Product | Support | NETGEAR

 

it'll have manuals and guides that go over install and getting that info.