Pls i need help in networking

Hello,pls i like to know the concept of routers,switches,hubs,modems and network interface cards,and the advantage of one over the other and the reason for using each.pls,it must be a layman`s approach.i want to know it like a child being taught by his/her mother how to write.again,why is a satellite earth station referred to as a hub?then,pls i need real life examples of how network devices make request or send frames or packets over a network.When i am trying to check my mail,by clicking the "login" button after typing my user name and password,am i sending frames or packets?if yes,how.if not,then how do i do it?infact,what is the difference btw frames and packets?thank you.