Anet A6 Firmware LCD Control

[maker5834]

Hello!I have uploaded Marlin 1.1.9 to my Anet A6. After installing the u8glib library and Anet A6 configuration files, I uploaded Marlin to my printer. The LCD was blank. I changed the LCD display from ANET_FULL_GRAPHICS_LCD to ZONESTAR_LCD (it is like the standard Anet A6 LCD 2004 but with five buttons instead of a dial). The printer LCD started and all of the information came up. However, when I tried to use all the options (PREPARE, CONTROL, PRINT FROM SD, etc.), I was just sent back to the homescreen. Attached is an image with the directions on how to set up the ZONESTAR_LCD. It says it needs ADC_KEYPAD_PIN to be assigned to an analog pin. I searched throughout the Marlin files and couldn't find out how to assign it to something. I would really appreciate some direction on what to do! Thank you!