The Mbed docs getting started is decent but cuts off after getting to blinky, and the important things to know about aren’t introduced in any particular order in the docs. So this aims to introduce the concepts in a proper order and mention some of the important things that are easy to miss like mbed_app.json and .mbedignore configuration.
Basically, avoiding some of the common pitfalls when starting with MbedOS6 like looking at docs for the wrong version or getting tripped up by the serial configuration. It also has some notes and examples.
You supposed to be able to use MbedOS 6 bare-metal as a replacement for OS2. Anyhow where have you found a local copy of OS 2 as I cannot find it online when searching for it.
Nope, that is not right. Some very low memory boards were not possble to use under MbedOS5 and their support were droped in MbedOS6. It was because MbedOS (also with bare metal) was still much big (binary size of simple Blinky) for that targets, how I remmeber.