Replenish AdBlue

Hello people knows someone how many liters of adblue at Discovery Sport fit in? What do you have to pay attention to when refilling cans you can simply buy from the store and refill it or must it be done with the dealer I have read on different pages that some have overcrowded it and it had to be drained again at a workshop With me stands a range of 2400 km for Def AdBlue how many liters should I refuel there Thank you