Hi Foizer,
If your remote does not have a mic button, you have a few options:
-Connect a remote with a mic button
-Download the SmartThings App on your mobile device and use the microphone from your phone
-Connect an external Alexa device
If you need more help, please call us at 1-800-SAMSUNG (available 8AM - 12AM EST, 7 days a week), or via live chat at https://www.samsung.com/us/support/contact/
~Samsung Advisor