Should you choose to self-destruct or be destroyed by players or NPCs out in space, you will be respawned via a clone.
If you have not set a respawn point, you will appear in a random system.
If you have set a respawn point, you will respawn there.
Once you have placed down a network node, you can right click and set as home base, this will act as a respawn point.
Alternatively, you may choose to respawn at an NPC location (Station). To do so you must be near the location, press C to go to character sheet and hit "Select NPC location".