Lots of C#.net 2008 projects in one solution file

C# project questions:
1. In a C#.net solution that was maintained by a team of programmers, is there a way to tell how to get the build to locate no errors when it is compiled. Basically I would like to know the order of items to try to get a large solution to compile.
**I am asking that question since the programmers that worked on this large application have moved on to other programming teams in the company. I am told that this C#.net 2008 application did compile clean 6 months ago and no changes have been made to the application.
Basically are there some suggestions you have on what to try to get the compile errors/warnings to decrease?
2. How can you tell the manner of how different projects within the same solution communicate with each other? Basically are delegates used,linq, DLLs, used?

I am sorry, but I do not understand "how to get the build to locate no errors". Are you asking that the build not show any errors? If that is what you are asking, then the choice is to either to not do the build or to fix the errors.

As for how projects communicate, a project is a collection of source code files and build options. Beginners often think in terms of projects. You need to think in terms of applications and executables and processes and threads. You need to determine what type of projects are in the solution and then determine how the software needs to communicate. The projects might be for a desktop application for a web site or for a class library and there are many other possibilities. You need to understand what type of applications each of the projects are for and then determine what needs to be done.