Simple logistic robot troubleshooting

Hey, I have just researched basic logistic robots etc. - so no "active" chests yet.

I have a very simple setup but it's not working how I thought it would and I'm not sure why.

What I want is for the red chest (passive provider) to be emptied of its contents and those contents sent to the yellow chest (storage).

Setup:

Roboport at full charge with a robot stationed in it.

Red chest full of stone brick, within range of roboport.

Yellow chest with filter set to stone brick, within range of roboport.

At the moment, the red chest is completely full, the yellow chest is completely empty, and the robots are doing nothing. I thought the robots would automatically take from the provider chest and store it in the storage chest. Is that wrong? Do I need to instruct them to do that? If so, how?

Thanks