How can i select multiple values in react js?

 Here i can pass only one value.but i want to pass multiple value.if i select multiple value but Db can take first value only

 SelectUserName() {  

      return (this.state.data.map(data => ({ label: data.UserName, value: data.Id })))  

} 

<Select  options={this.SelectUserName()} isMulti styles={this.customStyles} id="select" name="user_id" ></Select>