maltodextrin - what do I do with it?

[Sir Colin]

Hello, I hope someone out there can help me.
I have with my kit, a bag of maltodextrin with no instructions as to its use.
Do I add it with the sugar at the start of the brew into my fv, or do I add it with my priming sugar into my bottles after fermentation( I plan to syphon from bin to bottle without transferring to second bucket)? Would adding it with sugar at the start make the brew too sweet?

Thanks for any advice!