Hi Luis,

I would say that you need to watch the Leadpipe video again.
relax means that you should blow your mouthpiece and listening only air going out.
Then in that position, you should put the mouthpiece in the leadpipe (without the tuning slide) and the vibration should come hence the sound. Pulling off the mouthpiece of the leadpipe, and no lip vibration should be heared, just air.
That means you are pretty relax…