Choose a starting point
Create a new document with the Article starter. Enter your document identity and begin with a short paragraph so the first result is easy to inspect.
Give the argument a structure
Use Structure to add a section. Write a heading and a few sentences, then insert an equation with the available tools. The resulting LaTeX stays editable.
Compile and compare
Run Compile and inspect the PDF. Change one sentence, then compile again. Saving preserves the document; compiling refreshes the typeset result.