At the top of this very forum page is a link to download Bitcoin Core:
News: Latest Bitcoin Core release: 22.0 [Torrent]
You click the link under the number to go to the download page.
What you do next depends on your OS:
- On Windows and Mac there are installers on that page you download, install and run like a regular program.
- On Linux there is a portable .tar.gz archive of Bitcoin Core you can extract and run in the terminal like this:
cd ~/Downloads/bitcoin-core
./bicoind # or ./bitcoin-qt for GUI graphical node
Note: There is also a Windows .zip file that is portable and can be run using the same commands as above.