Many foreign learners have written about it. Essentially, one can follow conventions around oneself or try to write and get an English spelling that sounds closest to Hindi pronunciation. And there are no academic rules around it that one is taught in schools in India.

I learnt about IAST only after seeing how foreigners transcribe Sanskrit texts in Latin.

See this amazing article by a Polish journalist https://thediplomat.com/2021/01/spell-it-out-should-english-...