Write some Software , Design an App

We are looking for someone who can create a program or an APP that would allow us to play a video with an output of a selected video clip with graphic displays that can easily be modified to change the wording and what time they display. This video will be playing in a fitness class in front of people who are running on the treadmills. Video time is 15 minutes, the screen should have countdown timer, and other boxes [Speed] [incline] for an example check : [login to view URL] I want the program or app designed that I can pre-enter the speeds and inclines before the class, and play them during the class. For example, we would like to play a 15 minute video of a scene along running paths and trails. While this video is playing we would like graphic displays to appear on this video saying items such as "increase your speed by .3-.5" or "increase your incline to 2.0". We would like to be able to easily and quickly alter the words that show up on the screen and when they do. For example, in one video at minute 2 we would like it to say "increase your speed by .5". At minute 3 we want it to say, "increase your incline to 2.5" "increase your speed by .3-.5", etc. The next video we may want it to say at minute 1 "increase your speed by .3-.5" at minute 2 we may want it to say "incline of 3.0" If you need more explanation send me a message, I have a short demo video I made that I can send if needed!