Update Bolt Site by using this admin UI: https://bolt-docs-admin.netlify.com and sign in with GitHub account. If you have access to repo, you have access to admin.
Edits saved as drafts will create Pull Requests on the Bolt repo and then deploy an example site you can preview. Upon moving a draft to published, it will merge the PR into master and then deploy to live site. Using GitHub UI is not necessary, but can be helpful for feedback.
This uses Netlify CMS and any alterations to ./admin/config.yml will adjust site; just git push and wait ~60 seconds.
The Netlify site is hosted by Basalt and is configured here, but to be honest, there's next to no configuring there needed. It basically provides static hosting and a git gateway to this Bolt GitHub app.