tactile button input -- Solved

Other Hardware Sensors
2

You don't need external pullup resistors at all.
Pre-setup code:

byte pinX = #; // from 0 to 19 for Uno

In setup:

pinMode (pinX, INPUT_PULLUP);

with button that connects the pin to Gnd when pressed

In usage:

if (digitalRead(pinX) == LOW){
// button was pressed, do something
}