To create shipping type plugin you have to inherit from IShippingRateComputationMethod and implement methods from this interface.
1. GetShippingOptions returns GetShippingOptionResponse which contains a list of ShippingOption objects, which contains informations about shipping options like name or rate.
2. GetFixedRate returns shipping rate before a shipping option is chosen (for example, on the shopping cart page). If it returns null, customers will see in cart "Calculated during checkout".
3.HideShipmentMethods property which says if shipping methods should be hidden.
4. ValidateShippingForm is activated after user click continue button.
5. GetPublicViewComponent gets viewComponent name.
Example of viewComponent
Go to Configuration of ShippingPoint plugin then add shipping point.
Remember to activate shipping method
Now when client is in payment process he can choose your shipping point.