How the Lightning Network Sends Payments

I’m pretty new to the whole blockchain space in general and I was reading about Lightning Network. What message type does LN use to encode payment information? For example, in the book below there is a reference to the seven messages exchanged between channel partners.

https://github.com/lnbook/lnbook/blob/develop/07_paid_channels.asciidoc

However, none of them seem to transmit any information about payments. Like, “Bob, I’m giving you 10 Saturdays.”

I also looked at the Bolt spec repository on GitHub, but couldn’t find it. Am I missing something?