So im installing my base cabinets and now its time to set up the peninsula cabinet. I was given these 2x4 pieces and brackets from IKEA. Looks like i need to drill holes on the floor and i cant do that.

Any suggestion how to stablize and island/peninsula.

Im thinking of just using 2x4's all stacked up together and then shimmed or somthing

this is what they look like

https://m.ikea.com/ca/en/catalog/products/art/00298406/

i think they are kinda goofy