Thank you for the detailed error report, sorry if this is frustrating you looks like you did all the steps correctly.
What version of powershell are you using? It may be that since you are on windows 7 it comes installed with an old version of powershell and so some of the commands in our powershell scripts aren’t available. You can check with the following command:
$PSVersionTable.PSVersion
We’ve mostly tested on powershell version 5 so far so sorry for missing this dependency if its indeed the issue.