The violin hold
Holding the violin is very variable. Some players hold it high up, others low down. A lot depends on the player's physique and lengths of arms. In any case it should be held parallel to the floor.
It is held on the collar bone on the left side of the body with the jaw in the chin rest. It is not tightly clamped! A shoulder rest or pad may help (positioned below the violin supporting it above the shoulder) and this may make it considerably more comfortable. There are many different types available so ask around and possibly try a few before making a decision - the same goes for the chin rest.
The neck of the violin is held lightly between the fingers and the thumb which should be positioned vertically on the left side of the neck. The violin rests on the pad of the thumb so that the fingers are free to be independent.