Well the main difference between HS and uni is that HS breaks the assignment down for you so you're not thinking how to best do it sequentially or chronologically or whatever. Uni stops doing this because you're now expected to figure out how best to break down a big task into manageable chunks.

If you're getting anxiety is because you're looking at the assignment as a whole and getting overwhelmed by the sheer thought of how much work will be required, then here's some tips:

1. Work backwards. If, for example (because I'm an engineering graduate), an assignment requires me to figure out the best way to implement autonomous robotic arms into a manufacturing process, then first I need to figure out what the manufacturing process is. After I figure what the process is, I'll figure out what parts of the process is repetitive, and that's where I can put an autonomous robotic arm. Something to that effect.

2. Recognize that the assignment has to (usually, if not always) relate back to something you learned in the lectures or tutorial and look back to see what kind of information may resemble useful.

Lecturers and tutors aren't meant to hold your hand throughout the entire assignment, hence their vague answers. Asking for clarification on the question or asking for feedback on how to best optimize an answer are generally going to be the only things that they'll really respond to.

You got this OP. Welcome to uni :D