"No root directory found"

The Ocaml syntax is supported but I continuously get "No root directory found" when I save a .ml file.
I see that there is no `node_modules/` directory. I just created a directory, "added it to workspace" and "saved workspace as".
Can you give a hint about how to use (ocaml)reason-language-server the right way?

Is there a feature that generates the .merlin files without using Dune build tool (that generates them)?

Also, how do you enable the indentation feature? (ocp-indent)

Thanks

Version: 1.38.1
Commit: b37e54c98e1a74ba89e03073e5a3761284e3ffb0
Date: 2019-09-11T13:30:08.229Z
Electron: 4.2.10
Chrome: 69.0.3497.128
Node.js: 10.11.0
V8: 6.9.427.31-electron.0
OS: Linux x64 4.19.0-5-amd64

No source files or tests are named. Start by reproducing the error with a saved .ml workspace, then investigate how the language server finds a root directory and handles .merlin files, Dune, and ocp-indent; done means the setup guidance or behavior resolves the reported error and indentation question.

Written by the indexing model from the issue text.