Many people have replied these question, you can Google it. Since you are asking what soil it needs, what soil are you using? Hope not regular potting soil.

Buying a VFT this late of the year invites disaster, you don't know whether it is entering dormancy. Or it is actively growing but in shock after being shipped. That means if you forced it into dormancy when it is recovering, you may kill it. Big petioles, small traps, some malformed indicates its has been not receiving sufficient light.\

The most I can say is place it outside, to receive full sunlight, watering it with distilled water, the tray can be filled up. Let nature put it into dormancy, mines usually
enter dormancy late November.

Planting media is either pure sphagnum peat moss, or one part perlite & one part peat moss. Warning: Check the package of perlite & peat moss that it hasn't been fortified with fertilizer or wetting agents added to it. Also check the labeling of the the distilled water jugs, more & more companies are adding minerals or calcium to 'enhance' the flavor of the water. Some of these companies totally missing the point of the water being distilled.

WHERE are you located? You need to Google Venus Flytrap care and read. Unless we know where you are we can't help you much.

I am from Romania.

Well since your country gets below freezing in winter you will need to put the flytrap somewhere that temps. of about 40-45 degrees F. are kept. Mine go in the refrigerator.