This depends on the month you received your dahlias. Dahlias are not hardy and should be planted, in colder climates, in late spring or early summer. If you received your dahlias in early April, it is not recommended to plant them already.
To encourage sprouting, place the tubers in a one-gallon pot with moist potting soil, with the eyes or buds facing upward. Keep the pot in a dry and dark location and maintain consistent moisture levels, watering only when the soil feels dry to the touch.
If the soil temperature is around 60-65F and there are no frost signs, then yes, you can plant Icoon dahlias straight in the ground. But if you do live in an area with a warmer climate, such as USDA zone 8 or higher, then it is possible to plant Icoon straight in the ground.