How to increase speed light (Nikon SB-910) power when it's set to remote?

I'm shooting portrait and set up my Nikon SB-910 remotely behind me on a stand so the light can bounce off ceiling to the model. However the photos come out dark. How do I increase the power of my speed light*?

Thanks

*my SB-910 is not attached to my camera.

How are you triggering your speedlight - are you using the CLS system or are you using slave mode?

If using the CLS system, there's an exposure compensation control wherein you can change the intensity of the speedlight.

But the speedlight must be line of sight to your camera if using the CLS system. If the speedlight is behind you, it might not be triggering. So did you confirm the speedlight is actually firing?

And depending on your camera, not all cameras have CLS master capability. Only the advanced Nikon DSLRs do (D90 and above). If you are using a D3xxx or D5xxx camera, you must buy a SU800 to control the speedlight remotely.

If you are using manual/slave mode, then you can set the intensity of the speedlight on the speedlight itself.

But if everything is working, and the flash exposure compensation is not fixing the issue, then consider using an umbrella to bounce the light rather than bouncing on the ceiling… Especially if the ceiling is higher than 8~10ft.