What am I doing?

Amon, lots of stuff to change but I'm having loads of trouble getting my head around it as well.
This code 'runs' but doesn't do much...

Strict

Graphics 1024,768,16,0

Global particle_count:Int = 0


SetMaskColor 255,0,255
 
Global particles:TImage = LoadImage("particle.png",MASKEDIMAGE)

Type particle
Global particle_list:TList
	Field x:Int, y:Int, s:Int
	
	Function create()
	         If particle_list = Null particle_list = CreateList()

	
		While particle_count = 0
		
			For Local i:Int = 0 To 100
		
				Local p:particle = New particle
				p.x = MouseX()
				p.y = MouseY()
				p.s = Rand(3,10)
				
				particle_list.addlast(p)
				
				 If i:Int >=100
					
					particle_count = 1
					
				 EndIf
				
			Next
			
		Wend
		
		
		
	End Function
	
	
	Method destroy(p:particle)
	
		For Local p:particle = EachIn particle_list
				
			If p.x >1026 Or p.x < -2	
			
				p:particle = Null
				
			EndIf
			
			If p.y > 770 Or p.y < -2
			
				p:particle = Null
				
			EndIf
			
		Next
		
'		Return p
		
	End Method	
	
	
	Method update()
			x:+3
	End Method
	
	Method draw()
	DrawImage particles,x,y,0
		
	End Method
	
	
End Type


			
Repeat

	Cls
	
	
		particle.create()
	If particle.particle_list
		For Local p:particle = EachIn particle.particle_list
		Print p.x
          p.draw()
         Next
    EndIf
Rem
	If particle.particle_list
		For Local p:particle = EachIn particle.particle_list
          p.update()
         Next
    EndIf
End Rem


	
	Flip

Until KeyHit(KEY_ESCAPE)

Changes...
Global particle_list:TList moved into the Particle type definition.
If particle_list = Null particle_list = CreateList() added to the create function.
list.addlast particle,partical_list changed to particle_list.addlast(p) (and partical changed to particle)
p.particle = Null in destroy method changed to
p:particle = Null
Return from destroy method commented out (couldn't get it to work).
p.create() changed to particle.create() as the function belongs to the type and not the instances.
Following used to call draw() and update()

	If particle.particle_list
		For Local p:particle = EachIn particle.particle_list
		Print p.x
          p.draw()
         Next
    EndIf
	If particle.particle_list
		For Local p:particle = EachIn particle.particle_list
          p.update()
         Next
    EndIf

Draw and update changed to remove the for loops and the unnecessary ID...

	Method update()
	    Print "Update called"
		
         x:+3
			
		
	End Method
	
	Method draw()
	    Print "draw called"
	
			DrawImage particles,x,y,0
			
		
	End Method

Hope it helps.
<edit> ...and I reserve the right to have got this very wrong and missed a few changes I made. I think you used p.particle in some places when it should be p:particle.