If you are aiming at creating a webapp you can simply use it with latest released version of the SAFE Browser, we don’t have documentation for API yet though, but you can see some examples API calls in this electron example app: https://github.com/bochaco/electron-neon-safe/blob/master/renderer.js#L13
Just note you should find the Safe object at window.Safe() for a webapp, so change that first line to let safe = new window.Safe(); and the rest of the JS API calls should work the same in your webapp as in that example.