Once your wort has been cooled and transferred to a fermenter, you’ll want to prepare the growth media for pitching your yeast. As a rule of thumb, you’ll want to introduce oxygen back into your wort, since you’ve just boiled off all the oxygen with your hop or bittering additions. You can achieve this by simply pouring your wort into your fermenter back and forth, but this is risky, as it can introduce contamination. I typically use an O2 canister from any hardware store (about 10$), and this setup from Morebeer, I highly recommend this investment, as you’re guaranteed to have great yeast performance (providing the temperature control is correct, of course).
Simply attach the canister to the Oxygentation assembly, and sanitize the end before adding it to your beer (sanitizer or hot water). Turn on the valve slowly and aerate for at least one minute – right before pitching your starter.