Creating a new block can either be done by clicking Enter or Shift & Enter. From within the Hypernotes settings, you can decide which shortcut would match your writing flow best.

To open the Hypernotes settings, simply click on your profile icon in the bottom left corner of the screen. Click "App Settings" after that. 

Within the app settings, you will find a bar saying "New Block". Click on it to choose between only clicking Enter or having to hold Shift as well.