Step 1: Open the Project Page
Say someone recommended Subtitle Edit. Open its GitHub page: github.com/SubtitleEdit/subtitleedit.
The page describes what the project does. Take a quick look to confirm it is what you want.
Step 2: Click the Green Code Button
Near the top right of the page is a green “Code” button. Click it and a small window pops up.
In that window, click “Download ZIP” and your browser will download a compressed file.
Step 3: Unzip It
Find the downloaded .zip file and double-click to unzip it. You will get a folder with everything inside.
Note: some projects download as source code that needs “building” before use — but many offer ready-to-use versions under “Releases” on the right side of the page. The next article walks through Subtitle Edit as an example.