Procedures, functions, triggers, and types written in .Net languages are stored in .dll files. Once you create .dll file containing CLR procedures you should import it into SQL Server:
CREATE ASSEMBLY MyLibrary FROM 'C:\lib\MyStoredProcedures.dll' WITH PERMISSION_SET = EXTERNAL_ACCESS
PERMISSION_SET is Safe by default meaning that code in .dll don't need permission to access external resources (e.g. files, web sites, other servers), and that it will not use native code that can access memory.
PERMISSION_SET = EXTERNAL_ACCESS is used to mark assemblies that contain code that will access external resources.
you can find information about current CLR assembly files in sys.assemblies view:
SELECT * FROM sys.assemblies asms WHERE is_user_defined = 1