Canonical - WPMU Site Check

Was chatting with LIVE support and they had to go. They said open a ticket with this thread -

Ran a scan for - here - and it says a lot of things - the first issue says I have duplicate canonical tag

so we were trying to disable it.

Couple of more issues I need help with

1. Robots.txt file - how to add sitemap to robots.txt
2. Prioritize visible content - Above the fold optimization - how to do this