The Paste command places the contents of the paste buffer in the project. Where the entities are placed depends on the selections that are made in the Paste panel.
If you are pasting grid entities, you will have to make one of the changes listed on the Paste panel. Otherwise, the pasted grid entities will be removed immediately as duplicates. If you are pasting database entities, you can save them in the same place by just clicking OK or you can make one of the changes shown in the Paste panel.
The Translate, Scale, Stretch, Rotate and Mirror commands can be seen in more detail in the Transform section. The Project command and its options can be seen in the Project section. The Dimension and Distribute commands can be seen in the Dimension and Distribute sections respectively. The Re-Extrude command can be seen in the Re-Extrude section.