Shapes are the backbone of Tinkercad. They are what allow you to create and form new models. Learning how to use them is a strong foundation to building skills in Tinkercad.
To add shapes to the workplane use your mouse to left click and drag them from the menu onto the workplane.
You can have any number of shapes on the workplane at a time.
To find the dimensions of a shape click on it, and then on one of the white or black boxes arrayed around the edges.
White boxes at the corners will tell you the dimensions on the X & Y planes (width and depth).
Black boxes will tell you the dimensions along one plane at a time.
The white box at the top of the shape will tell you the dimension along the Z plane (height).
To free resize you can use the black and white boxes on the outside corners and lines of your object to resize it.
Clicking white boxes on the corners will resize X & Y (width and depth).
The top white box resizes the Z plane (height). The black boxes allow you to resize along one plane at a time.
Clicking any box along with the shift key allows you to resize the object relationally. (All sizes equally.)
Type a size in manually to exactly resize your shape.
To rotate a shape use the curved arrows to drag it in whatever direction you prefer.
The outer ring rotates freely, the inner ring in 20 degree chunks.
Press and hold Shift to rotate by 45 degrees, or type in your preferred degrees into the box.
To freely move a shape Left Click + drag it anywhere on the workplane.
To move a shape along a straight line, press and hold Shift + Left Click + drag the mouse in the direction you want the shape to move in. The shape will snap along a straight line.
Click and drag over multiple shapes to highlight them and move them at the same time.
Watch this video to see how you can have more control over where you set shapes and how you can align them with each other. This method makes assembling items much easier than moving everything manually.