any tips for those who are struggling with running?

i tried my first run today, my recruiting office holds weekly PT and it was my first time. i really struggled with my run. im used to working strength but never really did much cardio. i feel completely out of breath after a short period of time and had to walk for a good chunk of the run. i tried to keep going the best i could but i was just so out of breath. i feel pretty confident that i can get there with more practice but don’t really know the best way to start working in that direction or if theres any way to build up that endurance. any advice?