FMU export and import

Hi

I am trying to understand how to use FMU and have created a model and exported it as an FMU and the import it again using a FMU import block. I get the modell to work but when looking at the block parameters for the FMU it says there are "No data to dispay" for Parameters and for input ant output is says "This block contains no structured input/output ports." I can not see the parameters in the XML file either so i can not change the variability in the XML-file.

Why are not any parameters visible as a block parameter or in the XML and what does it mean that the block does not contain any structures inputs/output port?

Does the inputs/outputs need to be declared in some specific way before exporting the FMU?

Is it possible to change the visibility or tunability of parameters in the modell before exporting it as a FMU?

Kind regards Adam Johansson