How to prepare a ski trip to the Vallnord resort in Andorra?

Andorra offers many activities, including superb ski slopes. Some are more or less well known. The two best are Grandvalira and Vallnord. So how do you prepare for your trip to Vallnord, Andorra?   Preparing your trip to Vallnord   Which resort to choose?   First of all, the Vallnord ski area passes through several …