How to setup Visual Studio for existing Unity project?

Question

I have cloned an existing Unity project from git on a new machine, and the source does not include *.sln or *.csproj .

I have also downloaded Visual Studio from Unity Hub, but the editor doesn't work with Unity:

1. VS doesn't recognize Unity components
2. Unity doesn't update VS project (new scripts not recognized in VS)

I have selected VS as external tool for Unity, as shown here:

I also installed anything VS suggests (Mono, and a few plugins, etc). What's still missing?

The VS version is 7.7.4 and Unity is 2019.02

Answer 1

Problem fixed when I happened to re-open the project inside Unity:

Asset > Open C# Project

References:

1. Autocompletion not working in Visual studio
2. https://answers.unity.com/questions/1451377/autocomplete-in-visual-studio-wont-work-please-hel.html