This page lists some external resources one could use to learn more about TLA+ and related topics.
First things first:
Then as good kickstart to TLA+, start with Leslie Lamport — The Paxos algorithm or how to win a Turing Award. Part 1 and Part 2. It is a good introduction on TLA+ and uses Paxos and Consensus as an example.
After that, you can start digging into Lamport’s video course available on the website. If you prefer a written medium, Specyfing systems: by Leslie Lamport is still the reference book for TLA+ and its tools. It’s well written and easy to follow.
After learning some TLA+, it might be helpful to start learning some Pluscal. Checkout the pluscal page for more info and some resources.
Don’t just learn the theory, start by solving some small exercises.
A collection of resources about TLA+ can be found on the awesome-tla+ repository. Feel free to contribute with your useful links.