Is there a tutorial on how to set up a secure enviroment and use Electrum? Which OS to use? How to verify that the OS is secure? 

How to download and install Electrum securely? There are many methods - binaries, git, homebrew, Ubuntu package, building from source.

Is there a tutorial that has step by step instructions on how to set up a secure environment for Electrum and use it securely?
Here is check http://secure-bitcoin.blogspot.ru/, please leave a comment if you find any mistakes