Before you can stake your ADA, you first need a wallet. We recommend the official Daedalus wallet, which is the most secure full node wallet. You can download the wallet from https://daedaluswallet.io/.
Once you have downloaded and installed Daedalus, you need to create a wallet. You can easily do so by following the steps inside the program. It is critically important that you write down and securely store your 24 recovery words! You must have them if you ever need to recover your wallet. After the installation, please be patient as the Daedalus will download and verify the entire blockchain.
You will then need to send all of your ADA to your newly created Daedalus wallet. Do not keep your ADA at the exchanges, rather send them to the receiving address associated with your Daedalus wallet.
After your ADA is transferred, go to Daedalus Delegation Center, and click Stake Pools tab, and write Evergreen or EGRN in the search field.
Simply click on the pool, and then click "Delegate to this pool" button. Simply follow the step-by-step instructions, which will take you through the rest of the delegation process.