In my experience as a preschool teacher, children aquire language through immersion. If you goal is to have your child gain basic skills: counting to ten, hello & goodbye I think you could simply inset those phrases into your everyday usage. (Here we call that Tex-Mex
and it is just the way people talk!)
I can't speak to if it would be overwhelming for your child, although my instincts tell me to give it 6 months:
If your goal is fluency, then I have seen wonderful results with one person whom the child speaks to every day; such as one parent or a nanny; speaking and responding to the child only in the language you are hoping to teach. I have seen children as young as three be tri-lingual using this approach. That however was in the context of children without any major life trauma or adjustments.
I hope this helps, and I think that being multilingual is an amazing gift for your child.