2005 GS ameri-lite 24 foot w rear slide out not working

[Rich in Red bank]

:( just purchased a 2005 GS ameri-lite 24 footer with rear slide out queen bed.
Unit has been sitting for 8 months.
Battery is dead.
Plugged it into my house and van and the slide out will not activate and the motor makes no sound. This went on for about an hour then suddenly it slid out about 18 inches very slowly and then stopped.

The manual says to check the exterior electrical panel ( I cant find one) and the breakers and fuses in the interior box are fine.
I have no clue where to start , this is my first trailer and the manual couldnt be any more vauge and or useless, can anyone help?
:?

[Timothy]

You should have a fully charged battery before moving the slide. It will not work with a dead or low battery. If you battery was dead that long it's shot.