Hi, Intro, and a few questions 1989 Hi-Lo new owner

Hi everyone, new owner here of a 1989 22 foot hilo. The right wall has some moisture damage but luckily it appears to have come from snow packed against the side of it, and it is isolated to the lower wooden parts of the what would be the drivers side of the upper shell. Anyone have any pics of what the lower section (it is covered with what looks like white aluminum on the rest of the trailer) is made up of? It has rotted away on this one and no pieces were very large. There is a small amount of damage to the inner panels where water appears to have wicked up and caused some slight delamination on the interior, but for the most part i think that should be easily handled as the wall is still very strong and solid. Just need to rebuild the lower section.

Thanks in advance!