The first button in the Power Node menu is the Power Node addon preferences menu (gear icon). The next three buttons in this row will take you to the Power Node online manual (Manual), and the Power Node forums (Forum). The recipes button will take you to a special forum where you can share and request node recipes (groups) for whatever specific node editor you’re in. For instance, clicking the Recipes button while in the Shader Editor takes you to a special Shader Editor node recipes forum on blenderforums.org
To frame or group a selection of nodes, select them first then press “Group Selected” or “Frame Selected”. The main advantage of these buttons is that they will detect if the selected nodes are either a group or part of a frame and give you the option to remove them from the group or frame when selected. The Group Selected button is also useful in that using it will not send you into the newly created group. This is ideal if you need to clean up a large node tree by converting many of its areas into groups. You can also double-click anywhere inside of a frame to select all nodes that belong to that frame.
The field under “Frame Selected” presents the node’s label or node group name (depending on the type of node selected). This makes it less confusing to add labels to nodes or rename a node group. The down-arrow icon to the right of this label will become active when you’ve given a custom node group or node a name. This means you can click the arrow button to save the selected node or node group into your assets library.
Every texture node in Blender comes with a built-in mapping node. This option will become active when you have a texture node selected. Clicking it will display whatever selected texture node’s mapping options. You can use this menu to scale and rotate texture nodes individually. You can click on the Mapping, Inputs, or Outputs buttons again to hide their contents.