The 7 minute workout is pretty good. It's scientifically been shown to work despite being short, and there's a bunch of modifications to make the exercises more accessible if you find them too hard.
https://www.webmd.com/fitness-exercise/a-z/seven-minute-workout
There's a bunch of free apps that will talk you through the exercise if you want, or you can just find a YouTube video to copy along.
I second youtube videos. There's a ton of content available that's basically just advertising for the creator's app/book/website, but the videos themselves are often plenty to get started and figure out if you like that style of content or not.
Have you any studies that prove the usefulness? What I heard is that the evidence is rather flimsy and that, as a HIIT exercise, starting with it might lead to injury.
There's a couple of things to be said.
The evidence for most exercise programs is pretty flimsy. They all have problems with sample size -it's hard to find people that will take up exercise that haven't been already doing it, and here the evidence shows that it works about as well as you would expect another effective exercise program to do, rather than better.
It's not HIIT. There's no real on and off, it's just 7 minutes of fairly consistent intensity. It's also not that intense compared to say playing sport as a hobby. If you're worried about injuries, you want probably want to avoid impacting movements, and ballistic movement, and there's very little of that here. Probably the worst bit is the jumping jacks, which are still likely to be lower impact than going for a run.
Thanks, I'll take a look. I liked the idea of an app since it could track progress, so there may be something I can use there.