How do I plan my route?

How do I tell MapThis to tell me how to get to Point A to Point B? Can I do it within the system or I have to use the GMDL or nieko.net/tools/getroute.php ?

Btw, I'm from Singapore. We don't have GEODATA available for Singapore yet. That's why I need another way to plan my route.

I just can't figure out how to do it, been playing around with the SET Marker but I really can't tell what it's for.

Can someone kindly explain to me what's the Set Marker for?

Thanks...

See http://en.wikibooks.org/wiki/Map_This! for all that.