Placeholders can be used here, to represent the actual value...
E.g: "Hello [firstname]" will automatically be converted to "Hello James" when sending to a contact with firstname: James.
Available Placeholders are: [firstname],[lastname] and [group_name]
Please Note: that when using placeholders, the actual message length may differ from the lenght of the template when the placeholder values has been substituted.
It's so simple to be difficult but it's very difficult to be simple ...