What do i need to communicate my sensors with LoRaWAN, simply?
Base station means LoRa gateway.

Over 10 km would probably work but the modules have to be in line of sight. You can find range calculators on Libelium's site but it's better just to do the test.

Remember that using LoRa gateway means that you have to implement LoRaWAN network protocol. You have to handle resource-intensive code on yours mcus or buy modules with LoRaWAN already implemented like RN2483. If you don't have many sensors please concern using just peer-to-peer connection.