Then let’s start trying stuff that actually works. 
Say you have a single map, only one:
%{
"key" => "CUSTOMER",
"raw" => false,
"value" => "EOG.Acme.ManualXML",
"variable_type" => "env_var"
}
How do you get the customer out of it?
I am trying to walk you through the process, hence I am simplifying.
Stay with me here now and tell me how do you fetch a value out of a map?
OK, show me how. Go to iex and paste this:
map = %{
"key" => "CUSTOMER",
"raw" => false,
"value" => "EOG.Acme.ManualXML",
"variable_type" => "env_var"
}
Then, again in iex, show me how do you get "CUSTOMER" out of the whole thing.
OK, that will do for now. Now how do you make a map like %{customer: "CUSTOMER"} out of the previous value?
Right, now let’s modify the example. Now you have a list of maps. How will you process each element like that?