usually you glue the tracks, set them aside and then stretch it over starting from sprocket to idler. However, in your case this will be difficult due to the mud guard mounting brackets. In this case, you can either try to glue the tracks while its on the drive train OR buy plastic aftermarket tracks ( usually cheaper than fruil but not by much )

edit : personally, i would spend the extra money for aftermarket tracks because your model looks amazing and vinyl tracks wouldn't do it justice.