Somewhere at the beginning of your sales letter...at least based on some of the many high converting letters in niches that I have been in or purchased from.
It would be something like this:
Blah Blah Blah Blah Blah Blah Blah Blah headline
Blah Blah Blah Blah Blah Blah subhead
STOP!
Before you go any further, sign up for my free XXX day email course, xXXXXxxXXX
Benefit, benefit, benefit
Name box
email box
Continue with letter.
For example:
Magnetic Sponsoring
NOT AN AFFILIATE LINK
Hope this helps...