If you're on linux, use the openjdk build from your distro's official repository. If you're on windows, download the latest openjdk build from oracle (currently https://jdk.java.net/17/), extract somewhere, put /bin folder on path. Optionally set JAVA_HOME env variable to the main folder path. No clue about OSX but it's probably similar to windows.

Ignore oracle jdk, ignore any concept of LTS/not-LTS, that's only for companies with big pockets and specific needs.

People really like to make it sound more complicated than it actually is.