Skycity is a new take on skyblock, it is a modded skyblock in which the idea is to make your own city. Some of the standard tools you are use to aren't there - and you'll have to work out new methods to do them, or alternate machines.
This modpack is created around having fun, and getting a sense of achievement as you play though the challenges set out in the achievements book.
Good luck and most importantly, Have fun!
If your achievements book is broken, do the following:-
press esc, click on open to lan, click on enable cheats and click open.
Next in the chat text, type in /flushachievements