There is a lot of help out there to get you started with flow. Everything I have learnt up to now is from either YouTube, blogs or from the Power Users community.
Get yourself on the Power Users forum. They are great. There is one specific for Flow and you can find that here
Next up is YouTube. The main guy to go to is Jon Levensque, he is a Senior Project Manager at Microsoft and he really knows his stuff. His YouTube channel is excellent and has covered a lot of Flow tips and tricks as well as 1-2-1s with MVPs around the globe talking about all things Flow.
He also runs his own Flow blog here.