What is the difference between POR and PARA

Por and Para are both used to replace words such as 'for' 'by' or 'through'. PorPor is used to talk about movement, modes of transport and communication, exchanges, time duration and motivation/ reasons behind something. Examples I got in contact with her by email ; "La contacté por correo"I go through the park ; "Yo paso por el parque". I'll give you five euros for that top ; "Te doy cinco euros por la camiseta"I'm working for three hours today ; "Voy trabalhar por tres horas hoy"ParaPara is used to talk about destinations, recipients, deadlines, and goals. * NOTE Por and Para can often be used in the same sentence when talking about travel e.e "Yo camino por el parque para escuela"; "I walk through the park to school" *ExamplesI'm going to Italy ; "Voy para Italia"This gift is for you "Este gefalo es para ti"I have to do this presentation by Friday ; " Tengo que hacer este presentación para el viernes"I work hard to get money ; "Trabajo mucho para ganar dinero"There are also given phrases in which both POR and PARA are used;Por ejemplo. Para siemprePor favor Para quePor supuesto Para quéPor ciento Para dóndePor que Para ti