the short answer to your question is that there is a 'picking' system
you choose the objects that are relevant in your conditions, and then the actions only act upon those specific objects
MySprite 'is overlapping' ThatOtherSprite
now only the MySprite's that are overlapping ThatOtherSprites will have their angle changed, and only the overlapped ThatOtherSprites will be destroyed. If there are other instances of those two object types that are not overlapping eachother they will be unaffected by the actions following the 'is overlapping' condition.
All conditions work this way. it streamlines everything greatly
the longer answer can be found here:
http://sourceforge.net/apps/mediawiki/c ... Conditions
under the heading 'picking'
xenox is right though, look at this thread:
the ghost shooter tutorial is the quickest way to get a general feel for construct. I'll bet you'll be amazed at how wonderful everything works.
the tutorials in the tutorials section of the forum are more specific, so I would suggest picking and choosing through the 'are you new here' thread and wiki first