I don't understand nothing. Can you teel me one more time step by step?

//~menudialogue page=start title=Techmanual text=start blah..blah..blah.. text=end button=CH1.1,Chapter 1 - Buildings button=action:close,Close the Techmanual page=CH1.1 title=Techmanual - Buildings (I want to display a bitmap picture here) button=CH1.2,Page 2 button=CH1.3,Techtree button=menudialogue,Back to Chapter Menu button=action:close,Close the Techmanual
//~menudialogue page=start title=Techmanual text=start blah..blah..blah.. text=end button=CH1.1,Chapter 1 - Buildings button=action:close,Close the Techmanual page=CH1.1 title=Techmanual - Buildings (I want to display a bitmap picture here) button=CH1.2,Page 2 button=CH1.3,Techtree button=menudialogue,Back to Chapter Menu button=action:close,Close the Techmanual
//Lock combis (see combinations_xxx.inf) 		if (skillvalue("wood")<25){ 			lockcombi "branch"; 		} 		if (skillvalue("cooking")<150){ 			lockcombi "juice"; 		} 		if (skillvalue("cooking")<250){ 			lockcombi "wine"; 		}
on:skill_cooking { msgbox "Skill Info","sys/skillinfos/cooking.inf";} 	on:iskill_cooking { 		incskill "cooking",1,"Cooking"; 		$tmp=skillvalue("cooking"); 		if ($tmp==150){ event "skillup","global"; unlockcombi "juice"; } 		if ($tmp==250){ event "skillup","global"; unlockcombi "wine"; } 		if ($tmp==300){ event "skillup","global";} 		if ($tmp==450){ event "skillup","global";} 	}