First make a pledge for one reward. Then follow the instructions below to change your pledge amount to equal all the rewards you'd like to receive. For instance, add $59 to your pledge for a Solo Stove Lite etc. Then send us a message and let us know what your total pledge is and what items you'd like to receive.
You can keep track of your pledges through your Backed Projects page. https://www.kickstarter.com/profile/backings
In the active pledges section, you'll be able to see your current live pledges, the amounts you've decided to pledge, the rewards you've selected, and more important details. If you'd like to change a pledge amount or reward selection, just click on the project title next to the corresponding pledge and select edit next to your pledge amount.