"Kłaść" is the simplest way to express the idea of putting sth. Kładę talerze na stole. - I put/I am putting plates on a table. "Pokładać" is used mostly in the fixed expressions "pokładać nadzieję"/"pokładać wiarę" - to put one's hope/faith in sth. The difference between "kłaść" and "położyć" is based on the role of perfective and imperfective verbs in Polish and, in general. in Slavonic languages. I recommend you this short article, where I believe you will find quite clear, general explanation of this hard part of Polish grammar - https://en.wikibooks.org/wiki/Polish/Verbs The number of verbs with this specific meaning may be treated as a kind of equivalent of either phrasal verbs or verbs with prepositions in English. For instance: kłaść - to put, wkładać - to put in. Verbs with the similar meaning to "put" are i.a as follows - stawiać, lokować, umieszczać etc.