PostgreSQL https://www.enterprisedb.com/downloads/postgres-postgresql-downloads
I forgot what the installation process for this is like, but if it prompts you to setup a username and password, make it something you can remember. For instance, you can set both to be "postgres".
NodeJS https://nodejs.org/en/
Just download the recommended version.
Postman https://www.postman.com/downloads/
Same as the note for NodeJS.
Some Text Editor or IDE http://atom.io/ https://www.sublimetext.com/3 https://code.visualstudio.com/
Any of these will work fine. My personal prefernce is VS Code (the last one).