Opening a fresh Blender, you have 5 panels (from left to right, top to bottom):
Right Clickis for selecting (objects, nodes, elements,…).
Right Clickis for selecting multiple.
Up arrowmakes a panel fullscreen (
Down Arrowdoes the opposite).
Spacebaris for searching functions.
More shortcuts available in DDG by searching for “Blender Cheat Sheet”.
Note that shortcuts are the best way to move around in Blender and can save a lot of time. If you find yourself repeating clicking on the same buttons, look for the shortcut and use it. Shortcuts also behave differently depending on the context (the panel where your mouse is).
Tis for tools.
Nis for properties in the 3D View.
Tabswitches between Object Mode and Edit Mode.
Tab: switch between vertex, edge, face