Hi Chris
If you're planning on moving between the ski areas then I'd suggest thinking of renting a car from the airport so you have transport whilst on holiday. There's free parking in Arinsal, and then free parking at the El Tarter gondola.
If you don't have a car then you need to take a bus from Arinsal into Andorra la Vella, then a new bus from Andorra la Vella to Encamp (which is the first entry point to Grandvalira you'll come to). On the bus it will take around 60-80 minutes, depending on your connection time in the capital.
Steve
If you're planning on moving between the ski areas then I'd suggest thinking of renting a car from the airport so you have transport whilst on holiday. There's free parking in Arinsal, and then free parking at the El Tarter gondola.
If you don't have a car then you need to take a bus from Arinsal into Andorra la Vella, then a new bus from Andorra la Vella to Encamp (which is the first entry point to Grandvalira you'll come to). On the bus it will take around 60-80 minutes, depending on your connection time in the capital.
Steve