Stuck: BG collision with maps drawn with DATA

So, recently I have started using the "DATA" Map Engine. But, I have something that keeps me doubtful. The BG Collision. So, I also want a collision with a ladder, you can enter it, and then you can use it while pressing up or down. Please help. I'll appreciate it! _{*I have got it on a Thread and I will use this engine :P}

look at other people's implementations of collision if you want some good ideas as in, downloading their games and seeing how they made it

look at other people's implementations of collision if you want some good ideas as in, downloading their games and seeing how they made it

I can do that maybe... But the search engine from here sucks. Just shows me a few things that it found. _{But yeah I will use your technique...}