Attending to the very restrictive word / space limit, while at the same including all the relevant material is quite a challenge.
It might be useful to look at how others have managed.
The Abstract is an important element of the thesis, and will become a document in its own right if the thesis is registered within any database.
The examiners will therefore assess your Abstract both as part of your thesis, and as a potentially independent document.
In addition to the research context, there may be other relevant contexts to present for example: It can be difficult to identify the best order for sections in this chapter because the rationale for your choice of specific research question can be complicated, and there may be several inter-linked reasons why the research is needed.
It is worth taking time to develop a logical structure as this will help to convince examiners of the relevance of your research, and that you understand its relevance.
You will need it to be succinct, specific, descriptive, and representative of the research you have done.
There is likely to be a required format for the title page in your discipline, so you need to check what that is.
The good news is that you have already started writing if you have written any of the following in relation to this study: In each case the object of the writing was to communicate to yourself, your supervisors, or to others, something about your work.
In writing your dissertation you will draw on some of this earlier writing to produce a longer and more comprehensive account.