How would you go about connecting a 555 timer to a circuit with a 16x2 LCD display, which is already connected, to create a digital clock that counts the time? Do you have a sample of how this code would work? I have researched online and found nothing tangible.
Do not, under any circumstances, attempt to use a 555 as a time-keeping clock. It's convenient and easy to design and adjust, but it is not remotely stable enough. Either make an isolated clock generator from the AC line, or use a crystal oscillator.
Your best bet is probably to use an Arduino (one with a crystal, not a ceramic resonator). You can find code examples on the net that include the LCD, and you can easily customize them.
If you want to get fancy, use a Raspberry Pi or Beaglebone and implement NTP protocol to synchronize time with a network time server using your Wifi.