to proceed with the download press the shiny green button
First you're going to find your GamingChair.zip file (most likely in your Downloads folder).
You're then going to right click that GamingChair.zip file and click Extract All...
When a window pops up and asks you where you want to extract it to, you should click Browse...
When you're in the file explorer you should goto the destination bar and type %appdata%\.minecraft\versions and hit enter.
Once you're in the versions folder, you should just click the Select Folder button.
Once the destination selection is complete, you can now simply click Extract.
Now that all of that is done, you can load up your Minecraft launcher and select GamingChair as a version.