any minimum amount of MHC to delegate?
No minimum. The idea is you set up a node and ask people to trust you and delegate to you. Once you gain votes you take good care to protect your node. If you re-delegate your coins from one fair node to another - you don t loose trust. The system is meant that you never risk your coins but risk several month of rewards so you pick delegates carefully
how do we actually vote? Do we put our MHC at certain node for certain period of time? We get additional MHC if our node get rewards and lost our MHC if otherwise?