Starting with Security Assist is not always the way to go, just in this case as a test of the installation by itself. There is no recommended list for the order of installing the extensions, generally speaking I just try to install the extensions in the order they were released and do not experience any errors doing it this way. If you are prompted to replace any existing files you should select yes to all. Let us know if you have a specific conflict that causes you problems so we can look into it further.