I don't think you can install it without the command line, if you hosting provider doesn't offer out of the box support for FFMPEG.
First, you need to find a way to login to your server using SSH. This usually requires:
1. You need to enable SSH access for your server. You can ask your hosting provider how to do it for your particular case.
2. You need a SSh client in your computer. If you are on a Mac you can use Terminal (included). If you are on a Windows Pc you can use Puttu:http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
3. Once you have logged in, Download FFMPEG installer. This is the easiest way to install FFMPEG and with great codecs support.
sudo tar -xvf ffmpeginstaller.6.2.tar.gz
I will take a while, probably 30 minutes, depending on your server. after that just test it using:
Hope this helps.