Hi beltdrive
Congrats on the new tank.
You need to get a filter that will cope with a tank of about 200 liters, this is just over the capacity of your tank, but better is more than less. The Make of filter you buy is up to you and what you can afford.
There are many types of substrate that you can use. If you wish to grow plants then you can buy special soil for this, and then cover it with sand. There is the standard gravel, coloured gravel, Larger stones. Again the choice is what you personally like, and can afford.
Not much help, but the choice is yours.