Press Z to create a clone. It will have a unique ID displayed below them. You can select a particular clone by changing the 'Selected' value (shown in the top-left corner) with the left and right arrow keys. When a clone is selected, it will appear bright. All other copies are darkened. Clicking on a clone will select it too. Press X to delete the clone selected. Press C to greet the selected clone. Press V to make all the clones do a barrel roll. By the way, they like it when you drag them around the screen. This also selects a particular clone. Besides dragging, press W,A,S,D keys to move the clone up, left, down and right respectively.
Note: If you drag an older clone to where a newer clone is, that newer clone will be selected while the older clone is still being dragged. If you let go of the cursor, the newer clone will be highlighted (as it is selected). A global variable can be affected by a clone, but not a local variable. If a local variable is changed within the clone itself, it will not change the value for the sprite. And each clone has its own value for the same variable. This way, each clone can be uniquely identified, whether they have the same sprite or not. The deleted ID will be stored in a list, so when you press Z, the new clones get assigned the deleted IDs first before the unused IDs. Credits to the Scratch Team for the following sprites: Gobo, Nano, Pico, Giga, Tera. Credits to MV42Rises for the pen display sprite.