Why check a hash?
A hash is a fingerprint of a file: change a single bit and the hash is completely different. If the hash of your download matches the one the project published, the file is exactly what they released – not damaged during the download and not swapped on a mirror. For real trust, the published hash itself should come from the official HTTPS site or be signed.
The same check on the command line: Get-FileHash file.iso -Algorithm SHA256 in PowerShell or sha256sum file.iso on Linux. More in How Encryption Works.
MD5 is not offered: it is broken and browsers do not include it. Very large files (several GB) may not fit into the browser's memory – use the command line for those.