you can start with that

gridMovement.capx

'cause the image point is at the center of the sprite. If I don't offset things by half the width and half the height you will have half the sprite out of layout. But maybe it's not a problem for you (:

hmmm try looking at tokenat and tokenCount system expression.

http://www.scirra.com/manual/126/system-expressions

Dont use shape_1, shape_2 and shape_3 but an array

Else you will have to rewrite the whole thing for each

global text shape_all = "shape_red:shape_blue:shape_purple:shape_yellow:shape_green:shape_orange"
global shapeCount = 3  // number of shape you want
+System: on start of layout
  -> Array: set size to shapeCount,1,1
  + Array: foreach X elements
    -> Array: set value at (self.CurX) to "empty"
+On What you want
  Local text tmp = ""  // copy to keep the original intact
  +repeat shapeCount times
    -> System: set tmp to shape_all
    -> Array: set value at loopindex to (tokenat(tmp,floor(random(tokencount(tmp,":"))),":"))
    -> System: set tmp to replace(tmp,Array.At(loopindex),"")
    -> System: set tmp to replace(tmp,"::",":")
    -> System: set tmp to (left(tmp,0,1) = ",") ? right(tmp,len(tmp)-1) : tmp
    -> System: set tmp to (right(tmp,len(tmp-1),1) = ",") ? left(tmp,len(tmp)-1) : tmp

    -> System: set tmp to replace(tmp,Array.At(loopindex),"")

    -> System: set tmp to replace(tmp,"::",":")

    -> System: set tmp to (left(tmp,0,1) = ",") ? right(tmp,len(tmp)-1) : tmp

    -> System: set tmp to (right(tmp,len(tmp-1),1) = ",") ? left(tmp,len(tmp)-1) : tmp

clamp just limit values between a minimum and a maximum

self refers to the object from which you do the action.

awesomeSprite: Set X to self.myVar

is the same as

awesomeSprite: Set X to awesomeSprite.myVar

Damn I've been Kyat ninja'd

/On the layout there are four hidden objects called (book,table,spoon,lamp) each of them has at least 10 frames, so I can't create only one object and then calling a random frame.

You can... And you should!

Basically I would setup the layout this way:

A Sprite called 'item' in which you put your animation of book,table,spoon,lamp.

Name the animations properly.

Then if you want to call a random object

System: Create item
item: set animation to tokenat( pool , floor( random( tokenCount(pool ,",") ) ), "," );

item: is animation "spoon" is playing
  -> item: start animation from current frame

Ok, I think we are running in circle, you should describe a bit more about your game, the solution might be quite simple, but just asking for some specific feature might not be the correct angle to tackle this problem.

put all the hud object in a family

global number mXStart = 0
global number mYStart = 0
System: On start of layout
  -> hudFamily set xStart to self.X
  -> hudFamily set yStart to self.Y
Mouse: on Left Click
  -> System: set mXStart to mouse.X
  -> System: set mYStart to mouse.Y
Mouse: left button is down
  -> hudFamily set X to self.xStart+mouse.X-mXStart
  -> hudFamily set Y to self.yStart+mouse.Y-mYStart

The question you have to ask yourself is why you want to pick a specific instance instead of another. By answering this question you'll find how to pick it.

For example if you want to pick a specific instance because it's underneath the cursor

+Mouse: is over Sprite
  -> Sprite: set myCustomID to 1

customBoundToLayout.capx

nope Unique ID and Instance ID are automatically assigned on creation

By setting a unique ID arbitrary you would have risked it to not be unique anymore...