Advice for beginning Cardio and my routine

[beardedman]

Hello everyone So to cut it short I really want to be able to serve in SF near the future. I have a year left until my associates degree is complete then I will enlist. The real problem is i come from a more bodybuilding/weightlifting background. For years i have lifted weights and focused on strength and size. Now i have obviously reprogrammed myself to move toward functional fitness and calisthenics. I get my *** kicked on cardio. This is from years of cardiovascular inactivity and never having a solid base. I have rucked already a few times and do well but when it comes to running, biking, aerobic activity i can't even get a 2 mile run in without breaks and my ankles hurting. This as you can tell is frustrating but I am in no position to whine and quit on itIm by no means quitting as i have scoured the internet and these forums but can't really find something for try beginners other then walk/jog/run approach. Any QP's have any suggestions to get my weak butt running and finally becoming good at cardio? I also do believe its part on my weight as i weigh 206 mostly muscle mass which I'm in the process of cutting down dramatically. Thanks for your input do not hesitate to give back brutally honest feed back swell as regards to how frequent and what i should do cardio wise.
Im 5"8 206lbs

If your curious my routine critique at will( I've also read numerous forums and am ordering Get Selected book, also donated 50$ to the actual organization god bless the men of special forces. Let me know if Im putting to much emphasis on weights i just seem obsessed with being strong for the tasks ahead.

Day 1:
Deadlifts 5x5
Kettlebell Press One Arm
Pullups/Chinups
Bent Over BB row
Farmers Walks
Heavy Hammer Curls
Leg Raises
Stair Climber 20 minutes

REST:CARDIO

Day 2:
Squats
Lunges
Pushups
Dips
Overhead Press
Military BB press
Tricep Kickbacks
Flutter Kicks
Planks

Rest:Cardio

Day 3:
DB bench press
Box Jumps
Kettlbell Swing
Pullups
Pushups
Planks
FLutter Kicks