If your dissertation is well-structured, easy to follow, logical, and coherent, your examiners will probably enjoy reading it, and will be able to listen to your argument without the distraction of trying to make all the links themselves.
The only way to achieve a consistent argument throughout a piece of writing is by creating some kind of plan or map of what you want to say. It can be useful to think of the research question or topic going like a strong thread throughout the dissertation: linking all the elements of the study, and giving coherence to its reporting.
Moving from doing the research to writing a comprehensive account of it is not necessarily easy. You may feel that you know everything in your head but can’t see how you can put it into words in the most useful order. It can be helpful to break the task down into smaller, more easily accomplished elements. The process of producing your writing plan could go as follows.
It can be a good idea to put the word limit to the back of your mind at this point and concentrate on getting everything recorded in a document. You can always edit upwards or downwards later as necessary.
It is likely, and advisable, that you will not wait until the end of your research before starting to write it up. You may be required to produce one or more chapters for assessment part way through your research. The process described above can be used for any individual chapter you are working on. It is important to be prepared to critique and revise your own work several times. Even the early chapters submitted for assessment, and passing that assessment, may need to be revised later on. This is not a failure, but a positive sign of increased experience and skill.