This is difficult to advise as each location is different, however as a general rule of thumb we recommend placing display screens at the entrance(s) to the area you want to monitor with a SafeCount solution.
This can be either on the outside or on the inside, however it is vital that the screen is visible to people as they approach the entrance.
If they cannot see the screen with the "Safe To Enter" or "Do Not Enter" message, then they will not be able to take the appropriate action before entering the area.
In regards to display screen mounting, this again depends a lot on the installation location. It is entirely customisable and individual to each location, however the most common methods we have discussed with customers are mountings for tablets, wall mountings for screens/TVs and free standing screen/TV mounts.