Not a proper tutorial yet but wanted to put pen to paper documenting as I learn to help others as cant find a full list of fields/tags, expressions and possibilities 
Will be an ongoing post and any/all input welcome.
I will try and incorporate input into a full list/details.
REPORT TAGS
Reserved for list of report tags, potential uses, example reports.
CALCULATIONS
Calculating within fields
You can create calculation fields using multiple fields and or fixed values.
A basic example;
{REPORT TICKET DETAILS:=[TT.Covers.Sum]/[T.TicketNumber.Count]:(TEC.Tables.Area=$1) AND (TS.Status=Paid)}
This is from a restaurant statistics report I’m building although not complete in the screenshot.
It will provide a list of tickets for each section of the restaurant and bar with details on each ticket.
At the bottom of each section I plan to have a break down of statistics for orders per ticket as well as spend per head and ticket etc.
Method:
Begin the field with ‘=’ to show its a calculation then as in above example using = [ <field.a> ] / [ <field.b> ] square brackets around each field and the usual calculation characters ( + add, - minus, * multiply and / divide).
Reserved for calculations in reports and examples
####Supported Calculation Methods
[T.Field1.Sum]*[T.Field2.Sum] Multiplies Field1.Sum by Field2.Sum.
([T.Field1]*[T.Field2]).Sum Sum of Field1 * Field2.
[([T.Field1]*[T.Field2]).Sum]/[T.Field2.Sum] Divides sum of Field1 * Field2 by sum of field 2.LAYOUT
Reserved for layout methods and examples
EXAMPLE REPORTS
Reserved for examples and shared templates etc.
Reserved for future additions if required