As a fellow student enrolled at Stonebridge, perhaps I can help with your problem.
To successfully complete your assignments, here's what you need to do:
First - read through all the material in the green "lesson" booklet you've received (either posted or in an email).
After that you will have a sheet of questions you need to answer (usually 10 - 15 questions). Just read the questions carefully and answer with as much detail as you can... all the information is usually in the green lesson booklet you've just read.
Note: I tend to answer the questions in a Word document on my laptop and then email them to my tutor, but you can hand write your answers on a piece of paper and then post them to the College if you like.
Finally, your tutor will mark your work and if you pass all the questions, you will be sent the question paper for the next green "lesson" booklet, along with the marking sheet.
It's really easy, and hopefully after you've completed the first couple of assignments (or "lessons") you'll really know what you are doing! :)
Regarding deadlines... I've been told myself several times by my tutor that there are none. You can take as long as you like to answer your questions! (Although you must inform the College if you plan to take a break of 6 months or more from studying).
Hope that helps. If you have any more concerns, just let me know.