To access the Sands location, you need to restore the Caravan in the central location.

After this, you will be able to go to the Sands and complete the super events of this location: restoration of the Ancient Tomb, the Genie's Palace and Robinson Island.

You will also have access to the restoration of unique buildings of the Sands: Oasis, Resort, Lost City, Museum of the East, Eastern Station.

The Caravan is located on the right side of the central location.

You can start restoring it at any player level.

Restoring a caravan has 5 stages. 
Stage 1
Collect 12 water (Water Tower, Upgraded Water Tower)
Grow 40 crops of strawberry (Farm, Upgraded Farm, Megafarm)
 
Stage 2
Collect 6 seals (Administration)
Ask friends for 6 forms
 
Stage 3
Collect 20 planks (Cargo Port)
Collect 25 ropes (Textile Factory, Upgraded Textile Factory when collecting wool, tule, denim, printed cotton, linen, Venetian lace, silk, velvet, lace, felt, cashmere)
 
Stage 4
Collect 30 packs of seeds (Flower Kiosk, Upgraded Flower Kiosk, Flower Megamarket)
Collect 30 glasses (Summer House, Upgraded Summer House)
Collect 15 pens (Stationery Shop, Upgraded Stationery Shop)
 
Stage 5
Collect 20 umbrellas (Subway Station, Upgraded Subway Station)
Collect 35 ring cakes (Bakery, Upgraded Bakery)
Collect 9 bottles of "Crystal" water (Gym, Upgraded Gym)
 
After completing this quest, you will be able to travel to the Sands.
In the future, the Caravan can only be used to move to the Sands. It doesn't bring profits.