Open a terminal/command prompt in the extracted folder and run: make clean all :
Lazarus-main.zip is typically a source code archive downloaded directly from the development repository (often GitLab or GitHub). It contains the "main" (development) branch of the software, which is the most current, albeit sometimes less stable, version of the environment. Quick Setup Guide Lazarus-main.zip
Since you downloaded the (the zip) rather than an installer, you must "make" the IDE. Open a terminal/command prompt in the extracted folder
Once the build completes, look for the lazarus.exe (Windows) or lazarus (Linux/macOS) executable in the root folder. Why use "main.zip" instead of an installer? which is the most current
If you have downloaded this zip file, follow these steps to get it running: : Unzip the folder to a location on your drive.