To get the interface to insert items into the machine, you use the Pattern Encoder. You make a pattern with the inputs that you want inserted, and the output that it creates (you can overwrite the output slot in the pattern encoder, so for a glass crafting pattern you would put a sand into the input grid and a glass into the output slot in the encoder). Then you take that pattern and put it in a "processing" slot in the interface. That item will now show up as craftable in the access terminal/crafting terminal, and selecting it to be crafted will cause the interface with the pattern in it to eject the items in the input side of the encoded pattern into adjacent pipes/inventories (so in the sand -> glass example, you would put the interface with the pattern in it next to the input side of a electric/powered/blulectric/induction/whatever furnace, and when you tell it to craft glass it will eject sand from the network into the furnace).
For things you just want to do automatically, export buses are generally simpler, though - I find this method is more useful for things that you will occasionally want to have, but don't necessarily want to keep in stock all the time.
I've also been thinking about this and I thought "what if you make multiple 'stations' like that and use the dark cable to turn on/off parts of the network with the possible recipes depending on what resources there are in the network".
So for example you have 2 Plantball production lines, one uses Saplings the other Seeds. Normally it will use Saplings, but you can use a Level Emitter and Dark Cable to turn off that part of the network when you have (for example) 1 stack of Saplings left and then switch on the part of the network that uses Seeds to make Plantballs.
I have no idea if that would work though, it could be that turning off part of the network it's currently using also jams up the crafting process. And I don't know if you can even add/remove recipes by shutting down parts of the network.
btw, I love how this mod gives massive storage and easy transport quite early in the game. Don't think that this is a late game mod, you can have a 1K storage module and ME chest really early on and it is extremely handy (at least I love how it stacks items together, it keeps things a lot more organized).
Edit: Well I made small test network with my setup, using Fabricators to craft plantballs. It works in the sense that it disables 1 recipe and activates the next, but it does lose the queue for requested items when it has to switch (so you have to request the items again or however many you still need). What breaks the queue is when it loses the recipe it was using to craft something.
Also, you can't really make it stop when 1 stack is left because the items get transported instantly through the network, so by the time the Level Emitter switches the cable everything is already sent over to the ME Interface.