1. Materials we need.

2. Screenshot of some steps.

3. Finished and test.

Product list:

dtmf module   https://www.utsource.net/itm/p/8673747.html

relay          https://www.utsource.net/itm/p/8673177.html

jumpers wire   https://www.utsource.net/itm/p/7961311.html

More details, you can check the video on Youtube: