Really, if its a case of not being sure at what your doing, you should perhaps give it to someone who does, the potential for disaster is somewhat obvious here, and could end up costing you a whole lot more than what you paid for the car.
On the flip side to that:
An Alfa is a car that can't be left to it's own devices to tell you when there is a problem like other marques (BMW, AUDI) etc.
They all still go wrong just as much but an Alfa is sensitive creature, it needs owner input at all times in order to "bond" with the creature.
There is no better way to "bond" than to get your hands dirty and learn just what she needs when and where.
You will soon learn the do's and don't's, what works, what won't and that there is plenty of owners on here that will help with the doubt on what to tackle.
Just make sure you follow the manual, have the "correct" tools, plenty of "plusgas" releasing fluid and above all, patience!
We all learn by mistakes and achievements, it's human nature. The more you tackle, the more confident you will become about taking on other tasks.
A job that initially takes you three hours to do at first will see you completing the same task in one hour eventually!
There is nothing more satisfying than seeing your hard work and effort flourish as the Alfa creature springs into life all healthy and happy. Then there is the bonus that you have saved a packet on vet, er.... I mean mechanic bills
Good luck, you'll be fine mate... You will enjoy it... Eventually after many plasters, cursing and swearing