This app is handy for both first-time grillers and veterans. It can calculate your cook time based on the cut of meat, size, thickness, and how done you want it, it also includes a timer to tell you when to flip and when to take your steaks off the grill. The app has instructions for preparing over 100 different foods, recommended internal temperature guides and resting times. It allows for multiple simultaneous timers, so if everyone is having steaks but there's one person who insists on having a chicken breast...you can time them all. AND---it syncs with your apple watch, so you don't need to keep checking your phone.
The app is only available on iTunes and it isn't free: $2.