I made a few changes. The "???" means that I don't know why these are here. They do nothing.
The CD4017 wll not drive LEDs very well. I added 2N3904 emitter followers. You can try it without them, but you may not get much light from the LEDs. With the transistors added, you could change the 330 ohm resistor to 180 ohms for added intensity.
I changed your variable resistor to 100k, and added a 1k resistor in series. You should get a better frequency range with these changes. You might want to change the timing capacitor from 100uF to 10uF.