Your starter should be active with lots of bubbles and doubling in volume, each day. Do not get discouraged if it takes a bit longer, sourdough is a slow process, it takes time. Be patient, you will be rewarded for waiting!
Each day, combine half of your previous day mix (toss the other half in the garbage) with the unbleached (15 g) and wholegrain flours (15 g), and water (30 g). Mix thoroughly and then place into a clean jar and cover with plastic wrap. Use a piece of tape or elastic to mark the height of the dough. Let it sit on the counter for 24 hours.
After about Day 7, it may be strong enough to make bread, however it is best to give it some more time to become stronger, ideally give it a full 2 weeks to get strong.