Many of the options that were specified at the time you created your project can be modified later. Select Project Options from the Project menu to modify these options. Some of the options such as the assembler and project type are not modifiable, you are required to create a new project to change those options.
Unlike the wizard the Project Options dialog allows you to specify Debug or Release code. Each project type has a set of build commands for a release version and debug version. Selecting one or the other will decide which of the command sets to use when building the project. Selecting Debug will add information to your executable useful to symbolic debuggers.
There are also options to alter the display of files in the Project box. Enabling Show Project Groups will display related files grouped together in subfolders and Expand Groups will default the state of those subfolders to "open".
For a more detailed look at the command lines see Editing command line options