isolator 2 batteries

So when I started moving things to upgrade my wiring I see: Alternator -> Car Fuse/Distribution Block -> Car Battery would the proper setup be: Alternator -> Personal 2 way distribution block -> Battery Isolator -> Battery A -> Car Fuse/ Distribution Block -> Battery...

Hey, My question was this. I have a regular battery in my truck, that is still good, just not new. I purchased a 250 amp alternator, Kinetik 3800 battery and stinger 200 amp isolator. I am wondering what will happen when I install the new battery to my existing battery along with the isolator...