Two advices on how to start solving those:
1) All commands (that I can think of) are documented on Linux, somehow. Most of them are documented in 'man' or 'info' pages. Those reside on a Linux machine usually, but are accessible in the web too. If you want a task done, you'll first search (in the web for example, if you're too lazy to read a book
heh) for a command that sounds like it does what you want, and then read it's documentation to get a grasp of how it works. So, for example about permissions changement you would do a search for "Linux change permissions", get a lot of pages that talk about a command called 'chmod', and then you'd find out how that command works; for example by searching for 'man chmod' (manual page for 'chmod'). After reading the manual page you'll maybe want to test it, so get your hands on a Linux installation and see how it works. Or just search for an example if you like.
2) If you have no idea how to proceed, ask your teacher/tutor. That person is the one who is your first guide. If that won't help, you can ask here too, but don't expect direct answers; rather try to solve the problem, face a troublematic situation, present it here along with information on how you tried to solve it (and what caused a failure), and then wait for advices.
If you don't have a Linux machine, your teacher/tutor can't provide you with an access to one, you aren't going to buy or loan any books about Linux, you're too lazy to do a web search for documents and examples and just don't think it's worth it spending some time with your homework...then I guess you're not willing to get the course done from which you got this homework. If you want to pass the course, it means you need to do your homework to understand something about the subject, and it means you're going to do it yourself. Others (like we) can help you back to your boat if you happen to fall from it, but don't expect us to drag it to the harbour for you.