Saving your work is important. If anything hapens to interupt your work you will want a safe point to start back from.
When saving click on the file tab located in the top left. For the first save of the project choose the "Save As" option. This has been circled in red. then choose a location to save it to, and give the project a name. Any other time choose the "Save" option. This has been circled in green.
Next step is to doctor up the project with a theme.