@Ash4827 It should be a matter of downloading the version posted on http://pencil2d.org/download that is appropriate for your operating system.
Make sure you review if you are using a 32 or 64bit computer (this can be known in your system settings depending on your OS)
Also please note we can no longer support Windows XP or macOS 10.6 and below, other than that downloads for other versions should be labeled properly in the download page I just linked.
Pencil2D does not need to be “installed” it comes as a ZIP folder bundle with all the necessary files to run. You simply need to extract that on your program files folder and run it from there. In that sense it behaves like a portable application, so in theory you could even run it form a USB stick if you wish.
If you have any issue please look in the troubleshooting section below the downloads in the same page. And in case those instructions do not help you let us know in this same thread so we can assist you as soon as we’re able.
Lastly, if you are by any chance using Windows OS please read this guide to avoid issues with permissions: [Guide] How to Train Your Pencil2D (Windows)