Press 'F1' or Ctrl+Shift+P to access one of the commands.
You can access all functionality (besides opening the journal) from the smart input.
journal:day(keybindings:ctrl+shift+jorcmd+shift+jon mac) opens the smart input, seejournal:todayfor opening today's entryjournal:tomorrow
journal:note opens a dialog to enter the title of a new page for notes.
journal:open starts a new instance of vscode with the base directory of your journal as root