It's kind of like Legos. Connect them up and program the combinators.
Video: https://youtu.be/nXhzdyEKHjI
Programming:
1) Set the Assembler to make whatever you want/need.
2) Set the combinator with the ingredients and output product using negative values.
2.a) The total number of input ingredients should be less than 20 (e.g. between -1 and -15 roughly), or you will risk locking up the loop.
2.b) The output products are placed on the outside lane of the loop, so they won't interfere with the ingredients.
2.c) The maximum types of input ingredients is 4, which is limited by the Filter Inserters' five filter slots (one slot is used for the output product).
4) Place modules together for complex recipes.
Edit: Blueprint
Pointless Modular Loops - that work
Re: Pointless Modular Loops - that work
It shoudl be possible to set the recipes via circuit network, have you tried?