Level your van
The process of levelling a caravan is carried out in two stages – first, left to right, and second, front to back.
Do not use the corner steadies! They are steadies, not jacks, and serious damage might be caused to the van floor if you do.
Starting with left-to-right levelling, you will need some form of levelling device, and the cheapest option is a plastic ramp. As its name suggests, this is simply a ramp, up which the lower side wheel is driven to get the caravan level.