Hey there! The best way to improve on stamina is doing at least a couple hours a week of zone 2 training.
There are 5 heart rate zones; zone 1 is resting heart rate, then zone 2 is when your rate is elevated, but you can still maintain a conversation while you run. Generally this is a pace that you can maintain for several hours at a time without stopping. This is also called the fat burning zone, because you are running at a slow enough rate that your body will only need to burn fat, instead of depleting your glycogen stores.
Generally this means you will be at a slower pace, but this increases your overall lung capacity and heart strength by having the ability to pump blood more efficiently with less beats.
If you do a couple runs where you run like this, you should see a difference within 4-6 weeks.
Hope this helps! (edited)

Hey there! The best way to improve on stamina is doing at least a couple hours a week of zone 2 training.
There are 5 heart rate zones; zone 1 is resting heart rate, then zone 2 is when your rate is elevated, but you can still maintain a conversation while you run. Generally this is a pace that you can maintain for several hours at a time without stopping. This is also called the fat burning zone, because you are running at a slow enough rate that your body will only need to burn fat, instead of depleting your glycogen stores.
Generally this means you will be at a slower pace, but this increases your overall lung capacity and heart strength by having the ability to pump blood more efficiently with less beats.
If you do a couple runs where you run like this, you should see a difference within 4-6 weeks.
Hope this helps! (edited)

I agree with user Woodlandfairy but, also leg work outs so you don't get tired out fast in the long run, as your legs will be stronger:)

Yes I thought of doing it but I am not able to complete the workout often I feel lazy or either way I don't have time but I will surely do the slim thigh challenge after this one! Ty

Most workouts in general improve stamina, I've seen really good improvements in mine over the last 1 1/2 years of being consistent. Even improve flexibility and balance. Id recommended a program with hiit and cardio in it, as they are more intense and fast paced and should help out.

Can you suggest some workout programs w hiit and cardio?

What level of fitness are you? Beginner, intermediate, or advanced.

It looks like your on the 2019 2 weeks shred which is a good start.

What level of fitness are you? Beginner, intermediate, or advanced.

Intermediate? Like a 50/50 for both beginner and intermediate

Any of the shreds and weight loss programs have a good bit of cardio in them. Maybe check em out and see which one you wanna do.