I recently changed the gearbox and clutch on my fabia atd pd100

after having wheelspun up a hill the gear changes became suddenly very difficult and reverse lights engage even when not in reverse however I can turn them off by pushing on the shifter all the way forwards.

This and the fact it is easier to move the shifter right than left leads me to believe its linkages but is there another possible problem and how do I adjust the linkages.

Thanks