How to Apply the User Defined style to a para in Template Document

I have to author content into a saved Template or Document.
The Template have user defined Styles. like “Qustion Style”, “Answer Style” etc…While writing the text/content into the document i have to apply that particular style. How to achieve this?
As we apply Heading1 style as below

builder.ParagraphFormat.StyleIdentifier = StyleIdentifier.Heading1;

How we can applye

builder.ParagraphFormat.StyleIdentifier = StyleIdentifier.User ???
builder.ParagraphFormat.StyleIdentifier = StyleIdentifier.Question Style ???

Thanks in advance

Hi
Thanks for your request. You can use code like the following:

builder.ParagraphFormat.StyleName = "User defined style";

Best regards,

Yes It worked.
You guys rock!