Linux supports more than one desktop manager. Gnome is a decent one.
You can start a terminal in Gnome by right-clicking on the background and select open terminal here.
To start a text editor in Gnome, click on the OpenSUSE button at the bottom left of the screen and select accessories/gedit.
There are several buttons and menus that you can explore. But everything that you need can be started from a terminal, and that is all that is described in these notes.
KDE is another desktop manager. A KDE desktop looks quite different from a Gnome desktop.
To start a terminal in KDE, click on the box at the lower left of the screen. Select system tools and select terminal. You will be offered a choice of terminals. I recommend the Gnome terminal.
You will find other tools in the same place.