This app was mentioned in 5 comments, with an average of 2.20 upvotes
On Android download this app called Precision Boxing Coach. Learn the call outs and how to execute each.
It will help you with combinations.
Call outs are in numerical form so a 1 would be a jab 1b would be jab to the body. There are 8 punches you need to learn:
Most of these have a body variation except for 3,7, and 8. You can learn footwork and feints later but it's much easier doing it with a second person.
All of the comments already suggested are excellent advice, but one extra thing I would suggest is using a coaching app. I used this for shadow boxing at home but it works just as well for bag work. Get some cheap bluetooth headphones on to get rid of tangled wires and you're good to go.
https://play.google.com/store/apps/details?id=com.forslabs.boxingappFree&hl=en (Android)
https://itunes.apple.com/us/app/precision-boxing-coach-lite/id715053176?mt=8 (iPhone)
Ive been using this precision boxing coach app lately and really like it(although the audio can have some bugs) you set the timer and it calls out combos to throw https://play.google.com/store/apps/details?id=com.forslabs.boxingappFree
my b. the android version has a different name.
https://play.google.com/store/apps/details?id=com.forslabs.boxingappFree&hl=en
the creator has a few different apps that are cool but this is the best for workouts imo.
I've seen this one, and when I get a little deeper into my ability, I'm going to use it. There's a free version and a paid version for more advanced combos:
https://play.google.com/store/apps/details?id=com.forslabs.boxingappFree