You need to check your hand book, it should tell you the unlaiden weight of your car, & the maximum tow weight.
As a new caravaner, it is recomended that you do not tow a caravan weighing more than 85% of your cars weight. eg if your car weighs 1000kgs your van should not weigh more than 850kgs.
There may be a maximum weight limit on what your car can tow, this could be below 85% so you should never exeed this limit.
Also if you look under the bonnet at the ID plate, it should tell you the maximum loading on each axle & the maximum train weight. The train weight is the total weight of both the car & caravan together.
Hope I havent confused you too much.
G.