Make sure it's the file they published.

Paste it, get a plain answer

A checksum is a short code worked out from a file's contents, published so you can tell that the copy you downloaded is the right one. Right-click a download in the list, choose Verify checksum... and paste the code from the site. MDM answers The file matches or The file does NOT match. Nothing to install, and no command to type.

The common kinds, read as they are

MDM reads MD5, SHA-1, SHA-256, SHA-512 and CRC32 checksums. Paste the code as the site shows it: there is no list to pick the kind from, as MDM tells them apart by their length.

Ask before it's done

A finished file is checked at once. Ask while it is still downloading, and MDM checks it when the download ends. You can paste the code as soon as the download starts, and come back to the answer.

From the command line too

The command line's get takes --checksum and checks the finished file: the code in hex, on its own or named, as in sha256:…. One command downloads the file and checks it:

misterdownloadmanager-cli get https://example.com/big.iso -o D:\Downloads --checksum sha256:9f86d0…

The command line guide lists everything get takes.

MDM checks its own downloads too

The same care goes into what MDM fetches for itself. The helpers it can install for videos are verified before they run: yt-dlp against its developers' signing key, ffmpeg against its published checksums. MDM's own updates install only files listed in a checksum list signed with MDM's release key, which every release carries.