Update SQL with a stored Procedure

I have a stored procedure that collects data from 2 different tables, how
can I write a Insert sql statement to allow only one of the tables to be
insertable. The one table is just a lookup table.

Here is what I currently have :

I have two tables, Compant and CAffl.

Company has two fields, Comp_Num and Comp_Name
CAffl has three fields, CA_Comp_Num, CA_Affl_Comp_Num, and CA_Cmnts.

I have a stored Procedure that links the table in the following manner

CREATE PROCEDURE sp_CompAffl @Company_ID Float  AS
select  c.CA_Comp_Num, c.CA_Affl_Comp_Num, c.CA_Cmnts, co.Comp_Name
from CAffl c, Company co
c.CAffl_Comp_Num = @Company_ID
c.CAffl_Affl_Comp_Num = co.Comp_Num
order by

How do I insert a record for this stored procedure? I only want to insert a
record for the CAffl table, not the Company table, it serves only as a
lookup here.