Hey so i am not aware of how much knowings you have with this program, so i will just try and make a step by step, and the you can jump over the steps that you know.
Step 1: Adding the video to ATVO.
Go down on the left were you see the Widgets, Screen etc.. Here you will find one called Video.
Right-click on it to add a video file. This will ad the video to the program.
Step 2: Create a button for the video.
You can now make a button, again by right click on the buttons section on the right.
Then go to controls, a part of the 3 fans you have on the top left. Here you can program a button to do stuff like play a video
Step 3: Program the button
When you have the button highlighted on the right you can make changes to the button, go to the control tab and under Action click the 3 dods.
Here you can add actions that will happen when you press the button, change it to play video, and under target make sure that it is the video you want
Step 4: Open op the program and pres the button and the video will now play




