Firstly I'd advise using a stable release of anything if you expect it to work out of the box (and of course use the version of silverstripe it is stable against) - "rc1" means release candidate - aka something that may be a stable release but we don't know yet
This is likely *extremely* out of date. I'd check the silverstipe (maybe silverstripe-labs) github. Also there are a bunch of "extra" newsletter modules that will provide extra functionality - but the key is to search github - rather than this website. I know it doesn't make sense! I will be raising this issue to help get new users started easier...