Once reaching a 5% Quorum in the proposal phase, then the proposal will go to the next phase which is Exploration, which requires a baker to vote. If reaching quorum with ‘yay’, then testing will apply which requires no action from the baker. After the testing phase, the proposal goes through its final phase which is Promotion, which requires bakers to vote and reach quorum. If the proposal reaches quorum with ‘yay’, then the proposal moves on to the adoption phase. The Adoption Period provides a "cool-down" allowing developers and bakers some additional time to adapt their code and infrastructure. After the Adoption phase the proposal will automatically be implemented and upgrade the Tezos protocol. The quorum is a minimum participation threshold; so if a baker votes ‘yay’, ‘nay’, or ‘pass’, that contributes to the quorum of the governance mechanism.