I would suggest before opening another topic you think about what it is you want to ask.
If you ask the right question you will get the right answer.
You have opened a lot of topics in the last few days.
In the "detect collisions?" topic I tried to explain how some of the things you wanted to know can be done. If I wasn't clear about them or if you didn't understand you could have just asked me there.
I gave you an example in the last topic I answered of making detection sprites, to see if another person is in that spot. (overlapping first spot in the row).
Thre are many other ways to do it, but this could be a good start.