Hi Tlasz24
We can only ask that you don't try keeping an octopus at this stage. Years of experience shows that these super-sensitive animals have a nasty habit of dying if everything is not perfect.
To put it another way. If this is part of your coursework, and the animal does die, well that's not exactly going to reflect well on your grade. Whereas, if you pick another, less-challenging animal to keep alive, and there have been a number of suggestions made here, and you keep that alive and healthy, then that will reflect well on your grade. Should this less-challenging (let's call it a guinnea pig species) die also, then you clearly were not ready to move to the next step (and you saved an octopus, an expensive octopus, in the process).
There's a big difference between raising Artemia and Daphnia, and Octopus!
Please, use a crustacean for this experiment! You'll get varied data also, and can look at periodicity of moult.
Why not get a hermit crab and get a glass blower to build you a glass whelk. Then you can place that in the tank, the hermit crab can inhabit it (if you deprive it of all other normal whelk shells), and then you'll be able to monitor egg development through this crabs life cycle also (if you have a few males and females in there), and examine what that crab is actually doing within that glass shell (most people would never get to see this). It would make for some pretty sensational video.
You could probably get a glass blower to make you several whelks for the LFS cost of an octopus.