How to make Martian soil
https://en.wikipedia.org/wiki/Martian_regolith_simulant#MGS-1 has a link to a standard for Martian regolith that includes recipes. It will, though, not be trivial to replicate the grain size from the minerals. Silicate stuff is hard, one might need an expensive mill or grinder to produce it, or a friend who works at a stonecutter's workshop. Perchlorates are not included in the standard, yet, but maybe its healthier to leave that unimportant detail (slight sarkasm :-)) away.

Mind potential health risks !

Suggestion: maybe it would suffice for an A level project to visit a site where one could take away a basalt, grind it somewhere and sterilize it (heat it to >100°C for an hour or so).