Programatically assign permissions to things

I have several lists of things that I want to assign visibility permission to a certain level of my organization

In this case MyOrganization->Root->Th->TT 1  and console user group to the runtime permission:

How can I do it programatically?

There is a snipet for run time:

var params = {
principal: undefined /* STRING */,
allow: undefined /* BOOLEAN */,
resource: undefined /* STRING */,
type: undefined /* STRING */,
principalType: undefined /* STRING */,
collectionName: undefined /* STRING */
};

// no return
Resources["CollectionFunctions"].AddCollectionRunTimePermission(params);

And a snippet for visibility

var params = {
principal: undefined /* STRING */,
principalType: undefined /* STRING */,
collectionName: undefined /* STRING */
};

// no return
Resources["CollectionFunctions"].AddCollectionVisibilityPermission(params);

How do I change the parameters to set these permissions to a list of things?

I have this script  that will assign permissions based on array definition:

var thingsPermissions=[
   {"Organization Level":"MyOrganization->Root->Th->TT 1","usergroup":"gr1","TheThings":['thing1', 'thing2',....] },
   {"Organization Level":"MyOrganization->Root->Th->TT 2","usergroup":"gr2","TheThings":['other1', 'other2',...] },
....
];

try {
    var result = "";
    for (var i in thingsPermissions) {

         //the level of the organization 
         var org = thingsPermissions[i]["Organization Level"];

         //the user group that will have permissions

         var usrGrp= thingsPermissions[i]["usergroup"];

         //loop all the things and assign the organization and user group

         for (var j in thingsPermissions[i]["TheThings"]) {
             var currentThing = thingsPermissions[i]["TheThings"][j];

          //////////HOW TO ASSIGN PERMISSIONS?

         }
     }
}
catch (err) {
     logger.error("Service error in " + me.name + " at " + err.lineNumber +": " + err);
}