You will start seeing rewards after two epoch cycles. For example, if you delegate during epoch 468, you will not start seeing rewards till epoch 471. Epochs take place every 5-days.
Our friends over at Woodland Pools built a great tool that will estimate your payout date based on your stake date, along with a video explaining how the Cardano Delegation Cycle works.
https://www.woodlandpools.net/#/tools/payout-date-estimator