I used to have aluminum storm windows and they were such
a pain. And they were not energy efficient at all.
Mine were 'double hung', meaning they slid up and down.
to get a pane out you had to force it to one side, or the
other and the other side would clear enough that you could
tilt it out for removal. I'm guessing yours is the same
way, except you would have to lift the pane up enough so
the bottom could pull out a bit and then pull down to
slip it out of it's upper channel. The screen works the
same way and you may have to get that out first.
The best investment I ever made on my home was getting
rid of those windows and putting in vinyl clad double
pane insulated windows that tilt in for washing.

Picture would help. The release mechanisms vary from company to company.
Ron