The finding of appropriate equivalents of French equivalents for English prepositions present considerable difficulties, as the prepositions of both languages have great variety of senses, and they rarely coincide. E.g., pour can convey in a number of cases for, but in a number it does not do so. On the other hand, for is not always the English counterpart of the French pour. By careful reading and increasing practice you will acquire a true feeling of the various French prepositions. Try to learn them as set constructions and do not try to think through the English equivalent.
Consider about for instance. About has at least six meanings in English (approximately, concerning, around, up and down, of, just going to). Each of them may be conveyed by different French prepositions or expressions. For example,
Speak about an event = parler d'un évévenement
he was about to leave = il était sur le point de partir
he arrived about noon = Il est arrivé vers midi
and so on. You mentioned in. In (and into for that matter) cannot be conveyed by a single French preposition, as indicated by the following representative examples:
In an arm-chair = dans (!) un fauteuil.
In peace, in prison, in town = en paix, en prison, en ville
in Paris, in France, in Mexico, in Usa = à Paris, en France, au Mexique, aux aux États-Unis
I suggest that you consider seriously the comments of users @Lambie and @LPH. If you are a learner that prefers to learn in a systematic way then a grammar book like 'A French Reference Grammar' by H. Ferrar would be useful. Another jewel is 'English Grammar for Students of French; a better understanding of English grammar (your own, I suppose) will give you a better understanding of French grammar too.
FSE contains a wealth of information. E.g.
Ways to learn grammar innately?
Official grammar
French grammar resources without technical grammar terminology
HTH:-)!
