XAMPP portable is the same thing as XAMPP but with the ability to work from a portable drive.  The disadvantage is that some of the settings for the servers use specific drive locations (drive letters).  The instructions below allow for this.  You only need to do one of them but both are explained fully on the next two pages.  They are:

If you are not using Windows you will need to do some research to find instructions for your operating system.  As long as you only want to develop under Windows read this page.

If you find XAMPP reporting no available ports you should read this:

Servers listen on ports for incoming data.  Different servers use different ports.  Sometimes two servers try to use one port and that cannot work.  If XAMPP is trying to use ports (normally 80 or 443) and they are used already it will not start.  This can happen if you accidentally start two copies of XAMPP or if another Web server is running already.  In Windows Services look for IIS.  You can also use netstat to look for ports in use and what software is using them or download a simpler utility to do the same.  Then close down the other bit of software which is using 80 and/or 443.