Make sure and check out the blog post on it here:
https://www.jamroom.net/the-jamroom-network/blog/64/welcome-to-the-new-site-builder
It is currently beta, so you'll need to enable the BETA channel in your Marketplace -> Tools -> Release Channels section, then you will be able to install it from the Marketplace.
IMPORTANT!
Note at this time if you are running the existing Site Builder set of modules in production on your live site, please do NOT upgrade to this new Site Builder just yet. While it does support upgrading, we want to get feedback and more testing in with larger sites before we recommend you switch your live site to the new Site Builder. Instead, please install on a test domain/site (easy to do if you're using JR hosting) and let us know if you spot any issues.
Some things we are working on:
1) Right now the Image Galleries module does not have a Widget - we're working on it.
2) Only the Elastic, Lucid and NingJa skins have been updated with the new {jrSiteBuilder_menu} function in the header menu template - we'll be getting to the rest of the skins over the next couple days.
3) We are still working on full mobile support for the new Menu Editor - it will work but we've not done full testing yet on the mobile side.
We've worked really hard over the last month to make this new Site Builder easy to use and powerful - we hope you enjoy using it!
Please let us know if you have any feedback, suggestions, or run into any issues.
Thanks!
--
Brian Johnson
Founder and Lead Developer - Jamroom
https://www.jamroom.net
updated by @brian: 10/29/15 10:38:48AM