[radicalbyte]

.Net In a Nutshell, flip through it for the syntax reference and an overview of the APIs.

Download Visual Studio Community (if you don't already have it) then try out one of the project templates. The tooling is excellent and it's very easy to get started.

Then it depends on what kind of code you need to write. I work with web/information systems so the focus is on SOLID over pure performance. Using DI and TDD is more important than being an absolute language expert.

Drop me a line if you want more details tips; I've helped a number of people make the transition. Email is in my profile :)