you all seemed clued up enough for me to ask on here

ive got a nokia lumia, the operating system is ms7.5, im guessing its like other 'smart' phones, however im a complete technophobe and dont have a clue how to use it, ive gone to an o2 shop and they couldnt help either, i guess all these youngsters are better with iphones

basically, i cant edit pictures, so im guessing i need an app? but where and how do i get it?
i also need a new ringtone, as the standard nokia tone is annoying, same question again, how do i change it?
lastly, i cant seem to sent or receive pictures, but i think thats something im going to have to phone o2 for
cheers ta, thanks very moochos (from an oldie that prefers keypad slide phones)