Sorry about the delay in posting this, I'd tried to upload it Saturday, but hadn't realised there was another step needed before I could upload videos of over 15 mins.
References: Jesus promises peace: John 14.27 & John 16.33
Jesus promises their fear will turn to joy: John 16.18-22
Jesus' commission applies to us as much as the disciples: John 17.18-21 (see also Ephesians 4.11 and 1 Corinthians 12.4-6, 27-28)

The disciples knew that only God has the authority to specifically forgive someone's sins (and thus Jesus is God): Mark 2.5-10
How did the disciples act, based on what Jesus says to them in John 20.23? Acts 2.38-40; 3.19-20; 4.11-12; 5.30-32; 8.5, 22, 32-35; 10.43; 11.19-21; 13.38-39; 16.29-31; 17.30-31; 20.20-21