How to bind multiple applications to a domain?

Question

Blogs

So, I have some experience in developing simple web applications in php and rails, deploying the latter on heroku. Moving on - I want to tie them to a real domain, plus I want to blog in parallel. Need a kick in the right direction. Let's say my site is DOMAIN.COM (I designed it directly on NIC.RU itself without intermediaries of hosters). I want the following:
1) /blog - link to the blog, as I understand it, there are two options:
1.1) for those who are friends with programming - find free sources of the blog platform on github, deploy on your hosting (preferably a rail application, because with they have the most experience). What are the most common options here?
1.2) how those who are not friends do - I don’t know exactly how, but I can assume that there are ready-made sites with blogging platforms. All that remains is to link to my DOMAIN.COM/blog address, the question is how?

2) /rubyapp1, /rubyapp2... - deploy to heroku - link to appropriate path - is this possible on heroku? I also understand that something will need to be configured in my account on nic.ru?
3) the same, only PHP applications. You will need to find PHP hosting and perform procedures similar to paragraph 2, right?
4) Now I want to set up a temporary static homepage, is it the easiest way to do it on the same nic.ru, having issued the simplest hosting option with them?

Thanks for the answers, I would also like to point by point) You don’t need to chew thoroughly, at least approximately, so that some kind of picture of the above, connections between hosting and registrars, to whom to delegate what, and the like, emerges in your head.

Answer 1

on heroku it is possible if in the routes specify the blog and what is responsible for it. but the blog needs to be chained together with the rails app, the app alone should be