Choose Build or Build Solution to compile only those project files and components that have changed since the most recent build.

Choose Rebuild Solution to "clean" the solution and then build all project files and components.

Choose Clean Solution to delete any intermediate and output files. With only the project and component files left, new instances of the intermediate and output files can then be built.

Reference: https://docs.microsoft.com/en-us/visualstudio/ide/building-and-cleaning-projects-and-solutions-in-visual-studio?view=vs-2017