Engineering is a combination of construction work, repair work, maintaining a death machine that happens to produce power, and making sure the station contains breathable air.
Your core toolset is a small variety of tools. If you're an engineer, then you should have a belt on your waist containing one of each; if not, you can likely find them in maintenance shafts and in tool storage within assorted toolboxes and vending machines.
Most tasks will have explainers for how to perform them on examination; for example, if you're constructing a wall, it'll tell you the next step if you look at it a bit closer.
