It requires some thinking and setup work, the necessary steps are listed here or here, and there are some caveats regarding overdubbing listed here.
Please also keep in mind that with the method described in the linked posts you will only get 4 pickups, not 8, as you need a corresponding flex machine for each pickup for setup work (incl. clearing a pickup). Perhaps you might be able to expand this to 7 pickups, but I have not tried that.
But having to have a corresponding flex machine for each pickup is also a blessing in disguise, as it allows you to use the loop recorded in the pickup with all the editing & sequencing power of a flex machine.
EDIT: And each of the pickup/flex machines can be stereo, which is quite a benefit if you want to loop material that has already been treated with stereo FX.
Fun fact: Although I came up with the aforementioned method and have used it for several years, I am eyeing on the Lubadh myself. 