You only need to follow some simple steps:
1- Enter in a battle.
2- Drive your tank to a place you want to spec.
3- Press Ctrl + Shift + K
4- Type "vars.set cam_maxmove 0" (without quotes)
5- Press Ctrl + Shift + K or escape
6- Drive your tank away from screen. ( Try not to fell
)
And after you enjoyed spectating get back to normal camera by following these steps.
1- Press Ctrl + Shift + K
2- Type "vars.set cam_maxmove 5" (without quotes)
3- Press Ctrl + Shift + K or escape
To have a view of the map from a high point you need to go to a high place on the map, put your camera in the highest position above your tank using "Q" and then set camera speed to zero using the command. That way you will be able to look up over the map using "E", but the camera won't move down to ground level because of the command.
You can also try using other numbers like 0.3 or 1 to have a slow moving camera, that slowly follows your tank. This creates an interesting "Cinematic camera" effect, that would look great in video.