A string is comprising of one or more letters and numbers forming one or more words. Furthermore, a string might contain some symbols/special characters. In most cases you will note that inside strings there are only . (full stops) and , (commas) - but this is more convention than a fixed rule. Strictly, any number and combination of characters and symbols can be regarded a string - but that's way beyond the scope of this wiki.
Strings are enclosed in quotes, either 'single quotes' or “double quotes”. As all the factory macros use double quotes, you should adhere to that rule as well: always enclose strings with double quotes!
Also, this distincts a property's name from a property's value.
See from the example Timecode - Enable/Disable:
<step>ActionScript.SetProperty.Boolean("Timecode.Enabled", !Timecode.Enabled)</step>
“Timecode.Enabled”
is the name of the property - we pass it as string, and hence enclose i in double quotes!Timecode.Enabled
is the property's value (forget about the ! here - this is a logical NOT, see Control Structures.