The wallet itself is connected to the validator, and rewards are automatically distributed according to the tokens held in the wallet. The entire quantity held in the wallet will continue to be staked. This means that you will not have the ability to stake only some of your tokens. You can freely send and receive tokens in your wallet at any time, even while connected to the validator. There is no lock period. When staking for the first time, you will be charged a 2 ADA deposit and a Gas fee related to it (that's how blockchain works). For this reason, our Wallet will not allow staking if your balance is less than 5 ADA.
Rewards are distributed per epoch, and an epoch is roughly 5 days. The rewards are automatically distributed from the blockchain, so there is no action to "accept the reward". The rewards will be distributed to the wallet connected to the validator.
You can freely send and receive tokens while staking. Since there are no restrictions, you cannot (and do not have to) unlock staking. Since there is no unlocking, there is no lock period.