Once you open Texmaker you'll see that it consists of four windows.
The first window on the left hand side contains the structure of the document. Here you will be able to navigate between each of the sections of your code.
The next window is where you will write your LaTeX code and the content of your dissertation.
Underneath your code is a window which will show you any errors in your code once you have built it at least once.
Finally the right hand window will show you the PDF output of your work.
I will point out a few useful options to begin with and the rest you will meet as your skills progress.
In the edit menu 'comment' prevents the selected text from being included in the document when it is built. It therefore helps you debug your code.
The LaTeX and Math menus contain shortcuts to the most used commands in LaTeX. This is useful whilst you are just beginning to use LaTeX but as time goes on you'll use this less and less. It is faster to remember these commands and type them for yourself.
Finally the help menu contains the user manual.
Clicking on Quick View opens a dropdown menu which contains the options LaTeX and BibTex which we will use later. Leave quick build as the chosen option right now. Ensure that the next dropdown box has View PDF selected.
Underneath are two arrows and a dropdown box. This allows you to have several Tex files open and move between them. The cross closes the current file but keeps all others open.
Activity - Explore the menu bar.
The two vertical lines of buttons act as shortcuts to commonly used code.
The left-hand vertical bar opens further options in the first window. Clicking on one of these options will put the code into the document. To go back to the structure of your document click
The second line of vertical buttons contain more familiar shortcuts to text appearance and alignment. It also contains subscripts, superscripts and fractions.
Hovering your mouse over any of these shortcut buttons will inform you of their function.
Activity - Open a new document and try clicking some of the shortcuts.