Which one is better and how do I use these? (Baby oatmeal)

My girl just turned 6 months and is showing all the signs she is ready for baby food. Well her pediatrician recommended starting her off on oatmeal first. Do I just give her the oatmeal thinned out with formula or can I add the oatmeal to a sweet potato purée I make or what? I thought when she said we could start baby food it would be purées, not oatmeal so I don’t know what to do.

I’m a first time mom here and have so many questions on how to begin this baby food journey.