How to setup or define model input argument Scilab/XCOS?

Specific domains Xcos
1 
    case "define" then
        // default values
        x0 = [0; 0]
        k_stiff = 1
        
        // create object
        model=scicos_model()
        // provide name and type
        model.sim = list("SCGNC_example_sim",5)
        // define inputs and outputs
        // one inputs with a variable size "double" element
        model.in = 1
        model.intyp = 1
        // one output with a single "double" element
        model.out = 1
        model.outtyp = 1
        // set initial state
        model.state = x0
        // set default parameter
        model.rpar = k_stiff
        // define block properties
        model.blocktype = "c"
        model.dep_ut = [%t %f]

        // set block properties
        exprs = ["[0.0; 0.0]";"1.0"];
        x = standard_define([4 4],model,exprs)
        x.graphics.style = ["blockWithLabel;displayedLabel=SCGNC_example"]

1-I have read the model define but I did not understand the

evtin,evtout,state,rpar, all the other but there is no example and how certain value in rpar,exprs,state came?

2- How to define such value and what/why shape/size of the rpar,exprs,state are obtained?
3-From where the value came?