How to secure REST endpoint? Documentation not current!

Does anyone instructions on how to secure REST endpoint.

This link is not current:

https://help.imis.com/iMIS2017/Implementation/Installing/Configuring_the_iMIS_SOA_web_service.htm

Also, this important part appears to say the same thing twice:
Edit the applicationHost.config file under C:\Windows\System32\inetsrv\config. You must modify the applicationHost.config file to access the service at the application level.
Modify the following line:

change to: Also modify the following: change to:

JAck Donahue