Hi Pilou,

>> How do you attach something to a Macro node ? <<

A macro node is just an empty container until node circuitry is put inside.
To do something it needs input/s & output/s that may be connected.

Try double clicking on an existing macro to discover what is inside,
or alternatively create a new macro, double click on it, and add some node/s
include input and output from menu drop down, and then click BACK on the nav bar.

It will all become clear,

James