The mini-breakers for Landmark are located above the battery and to the right of the battery cut-off switch. Some are manual reset types and others are auto-reset types.
Look underneath (bottom) the breakers for a tiny little push button. Sometimes they look okay but in fact are tripped out. Press it back in and viola! Hopeully
From what I recall, the awning in fact does use one of those mini-breakers. Too my knowledge though, the interior lights do not. Rather, they are fused in the DC fuse panel next to the AC breaker panel inside the RV. Remove the DC fuse panel cover and look for any lit red LED lights. A lit light there means an open circuit that is connected to a load. So a blown or removed fuse - the light will be lit.
Can you tell us please, do any interior lights at all work or are they all dead?
Jim