Good source of PQ/M language help?

I'll try these and respond thanks.

Thanks that helps but its a dry document and not easy to navigate. I was looking something a bit more structured, particularly with practical examples.

i.e. one of the things I struggle with is the syntax for non-basic date handling. Most of the basic documentation only describes standard scenarios, but I struggle to find good help with things like dynamic date ranges such as fetching data in the previous x whole months. I could do it in SQL OK, but the syntax in M is more complex. 

FYI I've shelled out for this as it has good reviews and I tend to find the MS books generally well laid out with good examples and sample files. But they too can be a bit dry and hard to navigate for specific help.

https://www.amazon.co.uk/Collect-Combine-Transform-Business-Skills/dp/1509307958/ref=asc_df_1509307958/?tag=googshopuk-21&linkCode=df0&hvadid=310831942794&hvpos=&hvnetw=g&hvrand=15536125492401517305&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007082&hvtargid=pla-567636164535&psc=1&th=1&psc=1

I get the impression there are a plethora of resources for Excel, Power BI and Dax, but far less for M.