Let’s start with the blades of propeller.

Step 1: Drag a half- sphere and change its dimensions as shown below. Rotate it at particular angle

Step 2: Drag a hole box and rotate it to certain angle to create a sharp edge of the blade and place it as shown.

Step 3: Group them.

Step 4: Drag another hole box and again rotate it same as sphere angle and place it.

Step 5: Group them.

Step 6: Now, drag a solid and a hole cylinder from the shapes panel.

Step 7: Align them as shown.

Step 8: Attach the blade with the cylinder.

Step 9: Duplicate the blade.

Step 10: Rotate the duplicate blade and place it on the other position.

Step 11: As you know, Duplicate tool copies the path of your action. So, again duplicate it.

You will see that the third blade automatically adjusted to its position.

Step 12: Select the design and group it.

 Step 13: Change the color and your propeller is ready.

This is how you can create complex objects. Just keep practicing.