While roof-raking some of the snow we got last night, the rake got
caught on a corner piece of my vinyl siding and pulled it off.

I'm wondering two things:

First, I haven't been up on the roof to take a closer look yet, but do
these things just pop into place, or is there glue involved?

Also, I assme the piece that popped off is there for looks and does
not actually keep the moisture out, since there appears to be vinyl
siding behind it. Just wondering how urgent it is to get it put back
on.. I'd like to wait until we get a warm day before venturing out on
the roof.

Thanks,
Dan