Having issue with Email personalize with %%First Name%%

I have created an email template on Salesforce Marketing Cloud and I want to add %%FirstName%% personalization string to it. However, I haven't been able to do so after trying different syntaxes. Below is my current syntax:

 %%[IF Empty(@First Name) OR @First Name == "Unknown" THEN set @FirstName = "colleague and friend of NALRC"ENDIF]%%Dear %%=v(@FirstName)=%%,

I would appreciate any help.