When entering VR, you can decide where you want to land. By default, the center of the scene (=of the grid) is the starting point (=Spawnpoint). 

Position of the user's view/HMD

Regarding the position, the Spawnpoint represents the foot of the user. Which means that its first vision will be a bit higher than the spawnpoint position.

Choose a Spawnpoint

Before Entering VR, you need to select a SpawnPoint from AR/VR Panel. It searches in all the scene the Spawnpoints you've created.

You have 2 possibilities to create them : 

Choose an occurrence as a Spawnpoint

For that, you just need to select an occurrence, and create a component "Spawnpoint". By doing so, your occurrence will be visible when searching in the Spawnpoint list.

Create a SpawnPoint

Create a specific Spawnpoint from Create Menu which is represented as an occurrence in the product tree.

You can then select it and  place it wherever you want thanks to the transformation Gizmo. 

Keep in mind that a newly created Spawnpoint is located at the scene origin

 You might need to dezoom a lot your scene to find the gizmo to move your spawnpoint if your scene is far from the grid