hello all im new here and need a bit off help

i need a little advice mate on the following

i have just got a fiesta rs turbo and its not running right. Here is the
problem i think it is Its not running tho the engine does run. It suffered
from backpressure and oil went everywhere and I don't know the full damage
The engine runs at high revs, lots of white smoke. Reckon the turbo may have
been damaged but thats what im not sure about and i need some help if i need
2 get a new turbo or get a new engine all together
also when started it sounds like a desiel and its has blown the oil filler cap off
i have just been told that it is back pressure so what does that mean now
just turned the car over, after a week of sitting she started first time, it idles at 2000 revs with a bit of blue smoke. burning oil smell too but the engine doesn't sound that rough. possibly needing a new turbo sounds as rough as a hippy bus i suppose but no sounds of metal on metal is what i mean

could someone help me out a bit so i know what i need 2get hold off cheers jonny