The Accellera SystemC AMS Working Group released the 2020 edition of the SystemC AMS User's Guide. You will find the user's guide on this page:
https://www.accellera.org/downloads/standards/systemc
This version of the user's guide is fully compatible with the SystemC AMS standard released as IEEE Std. 1666.1-2016. It describes all the features introduced in the SystemC AMS language standard during the last decade. For example, the user’s guide now explains the use of the dynamic timed data flow capabilities, to make AMS system simulations even more efficient and running even faster.