The term 'iCloud address' implies an email address, so you might be better off using the email app on your Android device instead of the text messaging app.
I didn't go through your link but sending an SMS message to an email is pretty straight forward. Just put in the email address in place of the phone number. Most SMS apps can do this easily. Going the other way however is where it gets tricky. Sending an email to a phone as an SMS, that's when you have to know what carrier the phone number is on and how they @.com (at dot com) their phone numbers. I think Verizon is something like @vtxt.com, but each carrier is going to be different. smvim is correct though, it's going to be easier to send SMS to SMS and email to email if for no other reason than to just keep it simple.