The young man:

As I went to the topic of relationships, I have a question, mainly for girls. The first step should be taken, okay. The question is, what are the boundaries of this step, what is its beginning and its end?

Sympathy is immediately visible. Both genders are very interested in themselves. The first step can be the most ordinary attention, a special interest (I’m about communication) Ideally to discover such common topics (for example, a hobby – it’s very connective!Look at the person expressively, because for some reason you have distinguished him among others (hold a look, it is the first sign of honest interest!) If the girl is very shy or just speechless - invite for coffee (it is preferable to do this without witnesses).
The most pleasant thing in communication is non-obsessiveness, naturalness - just be yourself! If the person did not respond with reciprocity, it is simply not your person.
And about borders. I believe that the beginning of communication is not the time for expensive gifts. This time of joint leisure, the level of the exhibition / cinema / coffee is quite sufficient. If after several dates there is no response interest in you as a person (and not a sponsor, for example), you can safely assume that you have done your best and continue to demonstrate the initiative unilaterally stupid.
I wish you good luck!