AutoDesk has a good set of modules called "AutoDesk Learning Pathways". They have videos, quizzes and assignments to learn how to use almost all of their products. I would use the classes on AutoCAD and Civil 3D to get started.
The AutoCAD modules will give you basics of using AutoCAD. The Civil 3D modules will hone in on the specific features that Civil 3D has overlaying AutoCAD. Civil 3D uses AutoCAD as a base, so hence why it is this way.
Edit: Just confirming It is free.
AutoDesk has a good set of modules called "AutoDesk Learning Pathways". They have videos, quizzes and assignments to learn how to use almost all of their products. I would use the classes on AutoCAD and Civil 3D to get started. The AutoCAD modules will give you basics of using AutoCAD. The Civil 3D modules will hone in on the specific features that Civil 3D has overlaying AutoCAD. Civil 3D uses AutoCAD as a base, so hence why it is this way. Edit: Just confirming It is free.
Also LinkedIn learning has a pretty good civil3D training. You can get a 30 day trial of linked in premium to do the training for free
I used the LinkedIn learning to learn C3D for work. I highly recommend this aswell.
Or sometimes your library will actually give you free access to LinkedIn learning!
Some schools just have a free option. I know the California state schools (CalState and UC) both give you free access to LinkedIn Learning
Wisconsin DOT has put out some fantastic training videos for civil 3d, check em out.
Since you're a university student, check whether your school offers free "LinkedIn learning" through the IT department.
Also look at udemy web site. (I am not affiliated), but you can catch a sale for around 20 bucks for a whole course.