Hi! It’s so much easier with the sparkfun ATTiny programmer, but either way the connection points are the same.
Using jumpers (I used the ones that came with the Kastle!), bridge
Reset (1) to RES
Ground (4) to GND
5V (8) to +5V
Digital 2/Analog 1 SCK (7) to SCK
Digital 1 (PWM) MISO (6) to MISO
Digital 0 (PWM) MOSI (5) to MOSI
And then use the Arduino app to install the firmware. Kastledrum goes on the right, and Kastledrum_clk_lfo goes on the left.