In the System menu Help -> Controls Help, you can find main combinations that would ease your work with the Planner 5D.
However, if you are using a touchpad, that doesn't change combinations for you. You need to check your touchpad settings to understand which gestures simulate the right and left buttons and the mouse's scroll.
You can find that information in System Preferences -> Touchpad.
Usually, those are the settings:
the left mouse button = tap with one finger;
the right mouse button = tap with two fingers;
scroll = moving up and down the touchpad with two fingers.