I have my ATtiny85 microcontroller installed in a HW-260 development board (purchased from AliExpress). I program the ATtiny85 with the SparkFun Tiny AVR Programmer, the setup guide is here: Tiny AVR Programmer Hookup Guide.

On the SparkFun programmer the onboard LED is PB0. On the HW-260 the onboard LED is PB1. This is the code I used to flash the HW-260 LED:

#define LED_BUILTIN PB1

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
}

You can see the programmer settings I used in Arduino IDE in this screenshot: