php - prestashop module not showing in left and right column? -

i newbie prestashop modules development. have developed module. working fine in backend (like update , delete inserted values). when tried check function of module frontend not showing. code install module this

 public function install()   {     if(!parent::install())       return false;     if (!$this->registerhook('leftcolumn'))       return false;     if (!$this->registerhook('header'))       return false;     if (!$this->registerhook('rightcolumn'))       return false;       return true;    } 

the code hook this

 public function hookhome($params)   {     global $cookie, $smarty;     $value=array();     .....................     ............     return $this->display(__file__, 'filename.tpl');   } 

i have tried many methods show module in left column , right column of page not showing there.

but when tried transplant module admin->modules->positions->transplant module->hook into->displayhome (homepage content). worked in homepage content. want show them in left , right column also. have tried use live edit module not showing in left , right column @ all. can tell me wrong here? , suggestions appreciable. thanks.

when register hook in module, have define method call when hook fired. in case, have define following methods :

public function hookleftcolumn($params) {     // stuff on left column }  public function hookrightcolumn($params) {     // stuff on right column }  public function hookheader($params) {     // stuff in header }