So to get that reward we just have to hold that token (automatic) or we need to contact the devs with the proof of our stake?
You can think about it like it is mining, but only for those who participated in the crowdsale (some sort of Proof of Contribution). Even if some people contribute only 0.01 ETH, they will be able to release their extra portion from the Deco distributor contract over time. This rewards can be requested ones a day, a week or a year, they are commutative and the distributor smart contract has all public functions exposed to see what the payable reward for the particle address is and how much of them is already released.
Contributors just need to call “Request Reward” function starting from 1 May 2018 from their address and the Deco Distributor contract will automatically release a portion of the Deco tokens to them.
The Deco Distributor contract has the functionality for changing the ownership for the remaining tokens from one address to another. In other words, anyone can pass the remaining tokens as the inheritance or just simply sell the ability to receive the Deco tokens in the future.