1. Collate your notes
Now is the time to get together all your notes and organise them. Mind maps and concept maps can help you organise your thoughts. Try to identify themes and categories that would be useful for grouping the notes together. These themes and categories could later become sections of your essay.
2. Arrange your notes to reflect a possible argument
Your argument will be the thread that leads your reader through your writing. It will give the writing shape and purpose - having no direction makes the writing very difficult to do. You may need to do a 'discovery draft' or some preliminary writing to help you work out your ideas and argument. For help see finding your argument and also using sources and adopting a critical perspective.
3. Make a writing plan
It is very difficult to structure your material successfully without writing a plan. You need to remember to shape the writing so it has purpose and direction (look at previous section) Read this resource on structuring your material to help you arrange your notes to reflect a possible argument. When you have defined your possible sections you might find this synthesis matrix useful to help you organise source material to feed into your sections.
After doing a lot of research you should have a lot of data and notes from your sources. You need to manage all the information and work out the shape of your assignment, considering how you will incorporate the source material.