You can find a variety of training plans for cycling, running and swimming on the internet and on pinterest.
I’ve linked to a few here to get you started.
You’ll want to research a number of plans to find one that is right for you. Take into consideration the number of days you’ll be running and or cross-training (XT). Is that something that you’ll be able to work into your current schedule or will you need to shift some things around to make it doable?
100k Cycling Plan