Ok, by symbols I assume you mean like text and icons and buttons. Let us call these widgets.
If you start Qt Designer and select
New Project from File menu
An then select
Qt Widget Application in center.
Then give it a name
And press Next , next, and then press finished.
Now you have a default Gui project.
Click on Edit
Click on Forms
click on mainwindow.ui
you can now drag text, buttons and other widgets to the grey area in the center.
Also , you must read some docs to understand how to use it.
you can start with
http://doc.qt.io/qt-5/gettingstartedqt.html
