Alright-Im rebuilding my 250x and right now Im trying to get the timing set

When you turn the crankshaft to get it to TDC(top dead center) the manual says that its supposed to be in the compression stroke-How do I know if its on the compression stroke or not?

I did try to do it, but after lining it all up and bolting the sprocket to the camshaft, I turned it around a few times and lined it up to the "T" notch on the flywheel-however, the sprocket notches wouldnt line up.

Also, when lining up the "T" notch, is it supposed to stay there fairly easily or do you have to hold it there?

I dont know whats wrong-maybe I just dont get this whole timing thing, but it would help if someone could explain it to me.
Thanks a lot!
Will