Go to https://wallet.keplr.app/chains/sommelier, search for Chorus One from the list of validators, and click on it.
Enter the amount you want to stake (leave some amount in your wallet to pay for the fees)
Click on the Delegate button
Click on Delegate and then Approve the transaction in your wallet/ledger. You're now staking with Chorus One!
There is no built in inflation. However, Sommelier uses a unique reward distribution mechanism generated through the use of Cellars.
Consider Sommelier Cellars to be vaults where you may deposit valuables and earn a return. It differs from other vaults in that it operates on a particular strategy set by a cellar contract and is dependent on data provided by the strategy supplier. This collaboration between the two should result in a higher return than depositing in traditional vaults.