When filing for a K-3 Petition. You send the I-130 first right ? do you have to specify in that form that you want to go on K-3 route. And when you receive the NOA for I-130 does it tell you to send the I-129F along with the NOA ?? How do you know you have to send the I-129F with it ?

The procedures have changed. To do a K3, you can send the I130 and I129F together in the same envelope. No more waiting for the NOA1. You could still follow the old method and send the I130 and wait for the NOA1. But it won't tell you to do anything... the I130 is used for CR1/IR1, so it will be assumed that is what you are doing unless you send in the I129F on your own.

You should seriously consider not doing the K3 and just going with the CR1/IR1 anyway. It will get your spouse a green card shortly after arrival without additional paperwork, save the $1010 of AOS, allow work immediately etc. There is only a minimal time savings between the two these days.
Cheers

The procedure that most people are following at the moment, is to file both the I130 and I129F together. The proof of filing the I130 is that it's in the envelope with the I129F

This is done because of the horrendous time that USCIS are taking to cash cheques and send NOA1s. If you waited for your I130 NOA1 a good couple of months would have gone by before you even sent off the I129F.

No application on visajourney has been returned for sending them together.