Menu bar (at the very top) shows the ‘File’, ‘Edit’, ‘Object’, etc. These give you access to a variety of commands, adjustments, settings, and panels.
Tools Panel (on the left) contains tools for creating and editing artwork. Similar tools are grouped together. You can access them by left clicking OR click and holding a tool in the ‘Tools Panel’.
Panels (on the right) include ‘Properties’, ‘Layers’, and other panels that contain a variety of controls for working with artwork. You can find a full list of other panels under the ‘Window’ menu. Panels in the ‘Window’ menu can be added to the panels dock on the right or left freely floating in the ‘Document Window’.
Document Window (in the middle) displays the file you’re currently working on. Multiple open documents appear as tabs at the top of the ‘Document Window’.
Artboard (white “page” in the middle) is where you will create your artwork.
Illustrator has a very customizable workspace if there is a tool you cannot find in the ‘Tools Panel’ select ‘Edit Toolbar...’ (three dots at the bottom of the toolbar) 
and a list of all tools are available for you to place in the ‘Tools Panel’.
Selection Tool (V)
Direct Selection Tool (A)
Pen Tool (P)
Curvature Tool (Shift + ')
Rectangular Tool (M)
Paintbrush Tool (B)
Type Tool (T)
Rotate Tool (R)
Eraser Tool (Shift + E)
Shape Builder Tool (Shift + M)
Gradient Tool (G)
Eyedropper Tool (I)
Width Tool (Shift + W)
Blend Tool (W)
Artboard Tool (Shift + O)
Zoom Tool (Z)
Stroke and Fill Colors
Drawing Mode (Shift + D to switch modes)
Change Screen Mode (F)
Edit Toolbar...
