As Serafina said click on the camp once you have placed it. You can also camp from the overland travel screen, this will bring up the camp interface immediately but will have no party banter/animations. Once you have the camp interface activated click manage and then drag the party members to the roles you want them in. Check the box if you want to use your carried rations. If you leave it unchecked or are out of rations your hunters will hunt until you have enough food/rations which takes more time.
You are given 2 'everburning' torches in your inventory to start the game, these can do 1 point of damage to the swarms. There are 2 vials of alchemist fire and 2 vials of acid that can be looted in the prologue. But the Devs have heard the complaints and patch 1.02 is set to address this issue.
Originally Posted by Patch 1.02 Notes