Hi,
I understand that you want to create a GUI to change the value of the block parameters in simulink.
You can do this by creating an app in app designer with Edit Field components.
In the “ValueChangedFcn” of Edit Field components, you can use “set_param” function to set the value of your required Simulink block.
The syntax of “set_param” function is as follows,
set_param(‘modelName/BlockName’ , ‘BlockParameterName’, value);
If you want to launch the app after loading the model, app need to be launched from “PostLoadFcn” callback or else if you want to launch the app after hitting the “run” button, app need to be launched from “StartFcn” callback. You can find the callbacks in Model Properties.
For more information, refer the following links: