This is not really how you use the LTN network to your benefit.
I would like to suggest to give yourself an easier start with this fantastic mod, by installing the Warehouses mod by Angel.
Also, make sure that you use Loaders that can Sort items. If the ones you're using can't do that, then get others.
Start easy. Use small trains with 1 loco and 2 wagons. Do not limit the wagons to any goods. Just set the trains to go to the Depot, and have them wait for 5 secs of inactivity before taking on a new job. (That's basically ALL the settings that your trains need in LTN)
Build your Provider and Requester stations with 2 warehouses, one for each wagon. Load and unload your wagons with inserters. That will give you more control with LTN later on.
Build just 1 Requester station at your base (for now) and have that station request ALL the goods that you need. So, it could be set to need 8k iron ore and 8k copper ore for example. Your trains will then try to deliver the difference. If there's zero in the station, they will need to get the full 8k, but if there's already 4k copper ore in the station, they only need to deliver another 4k. You NEED to know how to set these requests at the LTN stations, otherwise the system won't work.
The trains will pick up the goods needed (using all wagons), drop the goods at the Requester, and then return empty to the depot, ready for their next random job.
Then have the Loaders empty your warehouses by sorting the correct items on the correct belts, leading to your smelters.
If your smelters require more ores than your trains can drop off at that single station, then consider building extra Requester Stations. Have a separate one for your iron ore and one for your copper ore, for example.
This is your working start. From there on, you want to add more control, but that's stuff for later. For now, you need your setup to just work.
I hope that helped!
Good luck man.