Your solution folder structure should resemble:
Solution Root folder
├── .sln solution file
│
├── Project1 folder
│ └── Project1.csproj (or .vbproj)
│
├── Project2 folder
│ └── Project2.csproj (or .vbproj)
.
.
.
Your solution folder structure should resemble:
Solution Root folder
├── .sln solution file
│
├── Project1 folder
│ └── Project1.csproj (or .vbproj)
│
├── Project2 folder
│ └── Project2.csproj (or .vbproj)
.
.
.