A VisualStudio solution is used as the container to store all agents that belong together. These agents will be installed as individual services using different docker images (one per agent).

Recommendation

It is good practice to group agents that are vendor specific into one solution even if they are using different vendor interfaces.
Only put agents into different solutions that should definitely not be deployed together.

In order to start, create an empty solution in VisualStudio. Remove any pre-created source files and projects. Create individual solution folders for every agent in the solution.
The Processor Architecture for the solution and the tests must be AnyCPU.