Jonas is feeling nervous about the upcoming Ceremony of 12 that he and his family are attending. They arrive, and when its Jonas's turn to go on stage, they announce him as Receiver of Memory. Due to this, He is expected to go to the Annex Room as his job, which is where he meets The Giver.
This first box is pretty self explanatory, as Jonas seems nervous about the upcoming Ceremony of 12 for him. This is while his mom is asking him if he's ready to go. Before he answers he thinks to himself, "i'm really nervous."
Jonas are you ready to go to the Ceremony?
I'm really nervous
And Jonas is announced Receiver of Memory!
In this image, Jonas is selected as Receiver of Memory at the Ceremony. This is what started the adventure with him and The Giver. He was obviously at this Ceremony with the whole community, including his family and friends.
LIVE CEREMONY OF DECEMBER
Relating to the previous image, here is when Jonas MEETS The Giver. That is WHAT started their adventure together, but here is WHERE they started it, on Jonas's first day of training in the Annex Room.