In Cities: Skylines, if you want to force a road to connect to the docks, you can follow these steps:

1. First select the type of road to be built. In the game, different types of roads have different functions and restrictions. For example, express roads are suitable for long-distance transportation, while ordinary roads are more suitable for intra-city transportation.

2. Hover over the dock you want to connect and select Road, then Place Road.

3. A red line appears on the screen indicating the length of the road. You can change the direction of the road by moving the mouse.

4. Place the starting point and end point of the road on the dock. When the road placement is completed, click the right mouse button to confirm.

5. If you need to further adjust the road, you can use the road editing tool in the game to make modifications. These tools can be used to add, subtract, or adjust sections of the road.

6. Finally, click on the road to start building it. You can choose from different building options, such as using in-game funds or using cheat commands to complete the building quickly.

Please note that forcing the construction of roads to connect docks may have an impact on in-game traffic flow and game balance. It is recommended to back up the archive before performing such operations to prevent unnecessary problems.