GPG Sign NEWBIE

[TOrpheus]

Hi,

I'm new to GPG world...

How do I sign my keys?

I've imported them via gpg --import 'file'

Then when I try to do:

gpg -a -se -r [e-mail] -o test.asc test.txt

I get a

gpg: no default secret key: secret key not available
gpg: test.txt: sign+encrypt failed: secret key not available

Then, when I go to

gpg --edit-key [e-mail]

then I type

sign

I get a

gpg: no default secret key: secret key not available

So, my question is how do I setup the DEFAULT SECRET KEY?

Thanks a bunch!