My question is about how to create music mashups from about 3-4 songs. I am a beginner and would like to learn. The proper software etc.
mashups are not difficult to produce if you know how to use the software. Just knowing which software does that is not enough.
Actually you can do it in almost every audio editing software these days but you should know how to operate first.
I suggest Fl Studio as it is easy to learn and has great features. Lots and lots of tutorials about it are available on internet (YouTube, forums and premium websites)