cakephp 3.x data not saving when Saving data into 2 tables with has many relation

I have two tables clients and branches branches has field client_id relation between them us client hasMany Branches and branch belongs to user, i have following code in my clients/add.ctp view file

<?php 
    echo  $this->Form->create($client); 
    echo $this->Form->input('name');
    echo $this->Form->input('branch.0.branch_name');
    echo $this->Form->input('branch.0.email');
    echo $this->Form->input('profile_link');

?>

and my controller code isas follow
<?php
    public function add() {

        $client = $this->Clients->newEntity();
        if ($this->request->is('post')) {

            $client = $this->Clients->patchEntity($client, $this->request->data, [
                'associated' => ['Branches']
            ]);
            if($this->Clients->save($client)) {
                $this->Flash->success(__('data has been saved.'));
            } else {
                $this->Flash->error(__('The data could not be saved. Please, try again.'));
            }
        }
?>

but data saved in the client table but not in branch table please tell me what should id do or whats my error is sorry for my bad english

if client hasHany branches you should do

echo $this->Form->input('branches.0.branch_name');
echo $this->Form->input('branches.0.email');

read the manual about it