Hi, you need to set from driver or from software driver properties.
a) If you are using direct printing from a system, then(In windows), go to printer driver properties (general and advanced tabs) and find the orientation feature. If you don't have an advanced driver with advanced features, then go to www.nicelabel.cl
and download it for free, selecting your printer model and brand.
b) If you have a software, then you should be able to see a button in the top that says "printer properties". You can normally access the driver properties from there, then you follow the instructions from a). The only problem about that is that it is normaly for testing properties, but not necesarily will solve your problem forever...
You can play winner by following a) step.