Let's say I have a website site.com and on the front page there are links to the directory Links. But also on the same site.com I placed other folders demosite2 demosite3 demosite4 and developing a design for other web projects. If there are no links on the front page to those folders demosite2 demosite3 demosite4 will google robot index them? Or do i need to put nofollow tag on each of those demo pages? Thank you
If there's no links to those pages anywhere then Google won't index them. But if any site that is (or will be) in Google's index is linking to those sites then they will be indexed. You should set up a robots.txt file and define that those directories shall not be indexed.
if those demo sites can't help your main site then i don't think its necessary to crawl and index it..