I know the stress of uni work and training, im completing my final year now and got my exams left to do while training for a triathlon. Put together a routine that is achievable while your working, because if you make it unrealistic and too much, you'll miss sessions, get frustrated, loose confidence and drop out.
I could spend all week with you talking about diet and training regimes because there are so many ways to go about doing things. All id say is:
a. Train atleast 3 times p/w
b. include atleast 40 mins cardio
c. inculde some light resistance training before if you want
d. include some core stability exercises (abdominal work) twice a week
e. dont starve yourself, eat well, but eat healthy
f. enjoy it!
when i say 'atleast' i dont mean 'thats nothing' i mean thats around where you want to start, because more nessercerelly isnt better (for the same reasons i pointed out earlier). Also dont be affraid to do cardio out the gym, i do non at the gym, i hate it, its boring. Nothing beats getting out on the road and getting some fresh air and catching some rays.
Stick to it, be determined, dont give up and you will se results. Hope that helps, its very general and basic but complicating thigns never helps when talking to someone just getting started.