By foot. From the parking lot at 5300 metres you'll see the first slightly lower peak, home to the ski lift. It takes about 15 minutes to scale. 15 minutes more takes you to the real summit. Since this is "the beaten track" you will not need specific hiking boots for walking to the top. If you looking for alternative adventures, try ex. mountainbiking downhill from Chacaltaya to La Paz. Agencies like Topas Bolivia can help you arrange this.
