so i thought i would take some pictures for you anyhow slavo. in these examples i am using aux 1 and 2 on an old nehringer 1602 eurorack. i'm using both aux 1 and 2 because in this example i am making a stereo fx send and return for a korg kaos pad III. in your case the fx send is actually an auxillary output and you could use as such for one send of foldback if you were going to use it live. and in this case i'm going to pretend that my aux 1 and 2 are your mono fx send output.
so: aux 1 and 2 (your fx output)
patch your cable to aux 1 and 2 output (fx output in your case)
your effects unit input
patch the cables you took from your output to the input of your effects machine
