To install Form Wizard Pro you need to extract the zip file and then assuming you are using the .NET 4 version of mojoPortal copy the contents of the /net40/wwwroot folder into the root of your web site using ftp
Note that I said the "contents" of the folder not the folder itself. If you do that correctly then all the files should land where they need to go and then you visit /Setup/Default.aspx to complete the installation. If you did not do that correctly then the files did not land in the correct places and it is not installed.
After that it should be in the list just like other features.
You also must be using a version of mojoPortal that is compatible with the version of From Wizard Pro. You can find out the version fo mojoPortal and of features such as Form Wizard Pro from Administration > System Information. You can also confirm your version of .NET there.
If you continue to have problems please provide very specific information about what steps you have done to install it.
Hope that helps,
Joe