Whats is a good interal computer case temp?

so if i may ask how do i set this thing up properly as im looking at the box now and it dosent give alot of info as far as the installation i must say this isnt a thermaltake one its a icute but i have a themaltake one on its way im hoping to recieve it tomoz but this one is abit confusing its got the power, lead four three pin sockets i prosume for all the fans and four two pin sockets for the senor i geuse one of the three pins go in the bit where the cpu fan is been powered at mo but im not to happy about that as theyll be four thing powered by this thing is this safe ?