I was stand on my head looking at the first tow photos on my desktop PC, then decided to swap to my laptop..
You can go in and edit your post, with a right side up photo.
a series setup will run all the hot water from the wood/coal boiler through the oil boiler, both will be heated by the wood/coal.
It is the easiest way to hook it up,. If you followed a Primary/secondary loop system, then you might be a bit more efficient.
But it will be very hard to show you from the photos how to do a P;S setup.
Can you do a line drawing of your current piping and show which way you plan on plumbing in the coal boiler??
We'll try to help..