A thesis document is needed for you as one of your requirements.
How do you start?
Ultimately, where should you start?
Topic, topic, topic.
To be able to come up with a good thesis, one that is centred and focused on the field of your choice, you need to have a good idea on what to write about.
Choose a good topic.
If you are and have been racking your brains for a really good topic, and you are certainly running out of time just by coming up with a good topic, fret no more. Go to your professor and ask.
Your advisor would have a list of dissertation topics, and all you need to do is to choose from the list, which would suit you best, as well as knowing the capacity of your resources, you would be able to know if a specific topic is best for you.
If you feel that the topic should not come from your professor, another way to get a topic would be to visit your university’s official website. You can and will be able to find a list of accepted and permitted topics graduate students can use for their dissertation material.
A drawback to these suggested tips though, would be the kind of topics you would be choosing from. Because these are suggested and approved topics from your advisor or professor, and those from the university, chances of getting a good topic, in terms of something fun and exciting, and entirely new. Not that their topics would be uninteresting, of course, but the probability of getting appealing and attention-grabbing topics might be quite slim.
So if you are thinking of creating a thesis that would not only be interesting but new, then you can create your own list. The disadvantage to this though, would be doing double research, even when you are still coming up with a list, to begin with.
So, with these suggestions in mind, choose what would best suit you, as an individual, and plan ahead. It always works to know that you have ample time to prepare, regardless of what search topic suggestion you would be doing. After all, for a really great dissertation work, you need to know where to start, start preparing, and ample time to work on it, as well as do research on it.