Hi
In short:
1. There are many ways to do it, but personally I would make the list so it contains several SceneObjects, one for each of the hidden objects that you have to find. These SceneObjects in the list should contain two sprites: one TextSprite with the name of the item, one normal Sprite with a line (to cross things off the list). Each line sprite should be set to be invisible (visible = false), and the Sprite name should be line.
Then you need a way to "link" your hidden objects to the corrensponding entry in the list. You could do this by using a naming convention, so if your hidden objects are called cat, dog, banana, etc. then your objects in the list could be called list_cat, list_dog, list_banana.
If you do that, and you are using a behavior for your hidden objects, in the behavior's onClick or onMouseDown function:
_['list_' + this.owner.getName()].getSprite('line').setVisible(true);
2. Just add a SceneObject for your button, and in its onMouseDown function:
wade.loadScript('myScene.wsc', null, null, true);
Where myScene.wsc should be replaced with the current file name.
3. Keep track of how many objects there are and how many have been found. You can create an event in the scene's timeline (in the Scene Properties in the editor) at time 0, and you can use it to initialize a variable like this:
wade.app.numObjectsToFind = 10;
wade.app.numObjectsFound = 0;
Then in your hidden object behavior's onMouseDown function:
if (++wade.app.numObjectsFound == wade.app.numObjectsToFind) {
wade.loadScene('congrats.wsc');
}
Where congrats.wsc is a scene files with whatever you want to show to congratulate the player.
I hope this helps, good luck :)