Disappear after 3 taps

You need the event and your taps increment should be taps++

like this, im using the touch start event because it detects more often than tap: 

var taps = 0

var event = script.createEvent("TouchStartEvent");
event.bind(function(eventData)
{
    taps++
    if(taps >= 3){
      // code here
    }
});

For the brand part, not sure what you want to achieve.

What are you trying to achieve with the brand part? Is it an object that should be disabled?

You have to first import the scene object at the top which looks like:

//@input SceneObject Brand

then inside the if >=3 taps put

script.Brand.enabled = false

Learn more here: https://lensstudio.snapchat.com/guides/scripting/scripting-overview/

Is that what you are looking to do?