Buying road bike

[Zen]

And if someone have successful stories about buying bike online without fitting it prior, please share your tips

I doubt there are any

Like which parts of my body to measure and how then put them on frame size. I'm sure that there are some "for dummies" guides about already and you can just give me a link

There are on-line guides for that

As it's rather difficult to buy a road bike here, and I will need to order it online anyway.

where is "here"?