I downloaded Star Conflict through the download link on the website, not through steam. However I saw that steam now had star conflict available. How would I connect my current SC client to steam rather than redownloading it? Thanks for any help 
Steam uses its own file distribution and management methods. Even though you arguably could drop some of the downloaded game files from your stand-alone client into the appropriate folder in Steam, I would not recommend it and let Steam download and build the game folder instead.
Â
This ensures all the files are present and located exactly where the client expects and ensures there are no issues with file integrity.