In John 20, what did Jesus do as he said to his disciples, "Receive the Holy Spirit"?

Answer: Breathed on them

Jesus said, "As the Father has sent Me, so also I am sending you," then breathed on them and said, "Receive the Holy Spirit."

“Again Jesus said to them, “Peace be with you. As the Father has sent Me, so also I am sending you.” When He had said this, He breathed on them and said, “Receive the Holy Spirit.”— John 20:21-22 (BSB)