As a beginner, if you want to use an existing CubeIDE project, it likely has been created with CubeIDE 1.x, in this case better start with the version in which the project has been created.
If you want to create a new project or pin-out, you may want to try the new way from start.
(this is also an "old way", for those familiar with the standalone CubeMX.)
* Install the standalone CubeMX; use it to import an example or create a new project for a known board or a custom board. See the CubeMX user manual for that.
* Make sure to select the Toolchain/IDE "STM32CubeIDE" in the Project Manager view. (This is actually the project type, not the toolchain in the proper sense). Select other settings there as you need. Especially note the Toolchain Project Location (where the project will be created). As usual, the path must NOT contain spaces and funny characters.
* Finally click on the "Generate Code" button.
At this step CubeMX will download and install all needed libraries and documentation for your STM32.
With luck, the CubeIDE project will be created.
* Now, refer to the CubeIDE 2.0 User Guide how to import the new STM32 project into the IDE. Page 43, Fig. 48.
Since CubeIDE is sort of Eclipse/CDT, you need a Workspace. If you don't have it already, just let it create a new workspace. Do NOT reuse workspaces from other Eclipse IDEs, including other versions of CubeIDE.
The folder where the project has been generated by CubeMX does not need to be inside the Workspace folder. (It can be, but this is not necessary). Just take care that the workspace folder path does NOT contain spaces and weird characters, and, of course, not on a network drive or other weird place.
* Import the project into the workspace.
That's all. Now you are ready to edit, build and debug your program.
Note that the actual toolchain (C/C++ compiler, linker, debugger) is part of the CubeIDE. You can see the toolchain name and version in the CubeIDE project settings. CubeMX does not know these details.
You can also create and use CMake - type projects rather than Eclipse CDT projects. Read on that on your own ;)
