Syntax
Personalization strings are enclosed within double percentage delimiters; for example, %%string%%. However, these delimiters should not be included when used in an AMPscript function (refer to Attributes). The containing string is case-insensitive.
NOTE: If the attribute name contains a non-alphanumeric character, then it must be enclosed in square brackets.
%%[
var @firstName, @age
set @firstName = [First Name]
set @age = Age
]%%