[CentOS] generate signing subkey

hello all

 I need to generate a subkey in gpg in order to sign my emails. I
already have a main key. how do I generate the subkey I need to
encrypt emails? I have already run gpg --gen-key

thanks

-- 
Here's my RSA Public key:
gpg --keyserver pgp.mit.edu --recv-keys 5A4873A9

Share and enjoy!!