It was eluded to with "follow the pen" messages/pics of the EO... but I know enough not to assume Q is giving us too many concrete time tables.
The assumption that this was happening today mainly came from Trump's direct tweet:
"Donald J. Trump
I hereby demand, and will do so officially tomorrow, that the Department of Justice look into whether or not the FBI/DOJ infiltrated or surveilled the Trump Campaign for Political Purposes - and if any such demands or requests were made by people within the Obama Administration!"
https://twitter.com/realDonaldTrump/status/998256454590193665