How to use the current repository

With the current readme instructions, after I opened the sln, I found that all the project files are reporting errors, what should I do?
How to use the current repository, is there a more detailed operation?

Start by reviewing the current README instructions and opening the repository's .sln to reproduce the project-file errors. Check which setup steps are missing or outdated, then update the repository guidance with a clearer operation sequence and verify that a fresh user can open the solution without the reported errors.

Written by the indexing model from the issue text.