I cant get my new WaveShare 1.28 to work

I have this dev board https://www.amazon.de/-/en/gp/product/B0CM68M8LR/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I am trying to get ANYTHING to work - but everything I do comes up black when uploading it.

I have downloaded the files from waveshare homepage and that runs. So I know the board is working.

In Squareline studio I have only one board to choose from under arduino - Should I choose my board there? can I add new boards?

Is there perhaps a good guide for this particular board? or any good advice to get it working. Nothing fancy just a text on the display will do fine.

Hope you can get me going

You probably have problems with your display-driver setup. The Arduino board-template in SquareLine Studio is based on TFT_eSPI library. If you can use that library for your display, it should be configured correctly for your device (pins, SPI configuration, SPI-speed, etc.). If not, you must rely on the libraries in Arduino IDE, I guess you have installable libraries/modules that support this board. New board-templates can be made for SquareLine Studio, we make them, others at this forum make them too, you might find examples of successful trials here at the forum by searching for ‘board-template’ or ‘OBP’, our official documentation about OBP is here: Open Board Platform (OBP) | SquareLine Studio
The usual way of making board-template files is first creating an empty project in source-code which only opens a basic window with a single pushbutton (in a ‘ui’ folder exported by SquareLine studio). I prefer commandline tools like CMake instead of Arduino-IDE, but YMMV. If it builds and runs fine on the board then you can make a board-template for SquareLine Studio out of it. The hard part will probably be getting the drivers working. It’s good if you already have working example codes as they contain the proper driver and display-setup. I advise you to inspect those example projects, and you can use a simple one of them as a base to build on. When it works you can try to create a board-template from it following our documentation… (You can start from the TFT_eSPI Arduino board-template already present for SquareLine Studio but you’ll need to replace its driver/main parts by the working code, in a way you’ll merge the two worlds into one, no matter which one you start with…)