Hello,
You don't install inside joomla.
The installation steps are as follows quickstart package.
1. download quickstart
2. Unzip quickstart to your local PC and upload to remote
3. Insert your info site database backup and restore sql quickstart
4. Insert your site title, email etc personal information.
5. Insert your administrator username, password & email
6. Finish installation and remove the "installation" directory
7. You are done. you can now call the site url
Support Team.