How do Install content purchased from forge

I was part of a kickstarter and it processed through the foundry marketplace premium content. I can’t figure out how to install it on forge.

I know it will use part of my asset memory and I’m ok with this but I can’t figure out how to install it.

This should provide you with an answer to your question : Installing/updating Licensed Premium modules - Docs - The Forge
You would normally just follow the Foundry instructions on getting the content linked with your Foundry license, and assuming it’s the same license on your Forge account (if you have more than one linked to your Forge account, only the first one can be used for validating purchased premium content, due to how Foundry’s DRM works), it will automatically be available to install on the Forge from the Bazaar interface.