Before they arrive: if they need a permit to park on your street, please sort one out for them. And if you can't be at home, please make sure somebody aged 18 or over is there for you (the installer can't enter your home unless there's an adult there – it's the law).
Your installer will call you to let you know they're on their way. They'll will have ID, which they'll show you when they arrive.
They'll ask you where you want the cable to go, and where it should enter your house. It could be buried under your lawn or flowerbed, or clipped to a wall. They'll even lay up to 10 metres in hard ground – under your drive or front path, for instance. They will NOT start any work until they have agreed the route and the costs with you.
They'll then lay the cable from the road to your home using the route you've agreed.
They'll make a hole through your external wall and thread the cable through. If you don't own your home, you'll need to get the owner's permission for this.
They'll clip up to 3 metres of cable to your internal walls (probably along the skirting board).
They'll connect everything, set up the system for you, and test to see that it's working properly. They'll also show you how to use it and answer any questions you want to ask
When they have finished they will make everything just as they found it (except for the small hole through your wall).