I made a shelf from someone's idea...the plastic soap dish with suction cups. I then strung up some silk ivy leafs (the leafs were original attached to wired stems) and tied them to the dish for additional cover, top of the tank, coverage. My little guy ignored it at first, then started to investigate and decided, eventually that he liked it and uses it from time to time. It's been dubbed the betta beddy by basket.
It was in with my betta that died not too long ago. He was the same way, took some time, investigated, then used. I think a week is fair from my experience. Don't expect full time usage...see it more as just another option within the tank. I also have mine near the heater...don't know if that makes a difference, but could.