How to retain search string when using pagination in cakephp 4? - cakephp

Question

I am using cakePHP 4 and I want to paginate my search query. I have users index page and when I search something whose resultant data exceed the defined limit of showing data. Whenever I search something I want the search string to retain in the input box even if I jump to the next page
public function index(){
$this->conditions = array();
if($this->session->check('conditions')){
$this->conditions = $this->session->read('conditions');
}
if ($this->request->is('post')) {
$data = $this->request->getData();
if(!empty($data['search_string'])){
$searchString = trim($data['search_string']);
if($data['search_by'] == 1){
$conditions = array('Users.id LIKE '=> $searchString);
}elseif($data['search_by'] == 2){
$conditions = array('Users.username LIKE '=>'%'.$searchString.'%');
}elseif($data['search_by'] == 3){
$conditions = array('Groups.name LIKE ' => '%'.$searchString.'%');
}
}
$this->conditions = array ($conditions);
$this->session->write('conditions',$this->conditions);
$this->paginate['conditions'] = $this->conditions;
$this->paginate['contain'] = ['Userdetails','Groups'];
$this->paginate['limit'] = 8;
$users = $this->paginate($this->Users);
$this->set('users',$users);
}else{
$this->session->write('conditions',$this->conditions);
$this->paginate['conditions'] = $this->conditions;
$this->paginate['contain'] = ['Userdetails','Groups'];
$this->paginate['limit'] = 8;
$users = $this->paginate($this->Users);
$this->set('users',$users);
}
}