Cloud formation - Setup guides

Hey guys, I am trying to use the Cloud formation for the first time to get a feel of it.
how do i write the yamls? is there an easy way to understand the CF format and structure

The AWS docs:

Each resource has some examples, I usually copy that as a starting point and work from there.

the doc is super helpful. thanks

May i ask how to learn about nested CF templates and what is a service catalogue?

You ought to absolutely have a solid handle on vanilla Cloudformation before ventuing into nested stacks.

Service catalog is orthogonal to cloudformation.