Hello Petr,
It depends if the entity that you want to show on the page(the parametre of the page) already exists but is not yet accessible in your microflow you can retrieve it from the database, if it is already accessible in the microflow for example your microflow parameter CHEWS Areas you do not have to create it anymore and give that as the parameter. If it is not existing and you want to show information of the parameter on your page or you want to use your parameter on your page then you have to create it.
Hope this helps
Good luck!