"Add new item" button: It will be not in topbar, but as floating action button in bottom right corner.
Search modal: It will be basicaly the same - showing from bottom with cross to close.
Items: They will use standard "item ui" instead of "list ui" they're using now. there will be only 2 actions - add (plus icon in action area of a card) and info (main click event on whole card; new tab with information).
Search field: Standard bordered text field with clear button. It should be the same width as item container (now it's wider).
Add new item button ("plus button") shouldn't be in topbar but it should be as main action button on the page.