One of the best places to start are the tutorials that Google actually provides.

The first actaully can be useful for a starter.http://www.cboe.com/ The CBOE has some tutorials.

Hey @Matt Kowske, I was just getting started and have read almost the full tutorial on GC but I was wondering about implementing it for my first property.I like the separate hierarchy of accounts but how did you get them to interact?

Grab some joint compound and find a short sheetrock patching tutorial on YouTube.

Great tutorial as usual, Brandon Turner!

Is there a tutorial or can someone offer advice on navigating the site?

@Bill G @Justin SThank you all so much for the wonderful tutorial.  

Here you go:Estimating ARV Tutorial Thread

So I would actually say that even though most tutorials are aimed at NPNs, a lot of the information is very useful/relevant when looking at a PNs, especially when it comes to doing due diligence like ensuring title is as expected (you don't want to buy a 1st lien and find out you're now junior) and valuing the property (e.g., through a BPO).

Are there any online tutorials?