Doors and Windows - Affixing threshold

I posted about a month ago with a question about repairing some rot in the bottom of a door jamb...well, I tackled the rot problem pretty well I think but now I have to install the threshold. I have a metal one that sits on top of wood that I custom cut for the space. The wood plank rests on concrete and I'm unsure as to how to affix it so it does not move. It is pretty snug but can move back and forth a tiny bit and this has me concerned. The metal thresh is screwed firmly into the wood board but I now need to anchor the wood but how do I do this with concrete underneath? Are there special masonry screws that can be used for this? Would I need to predrill or use a special bit and drill? I'm almost there with the repair but stumped on this. Figured I would ask the experts here before schlepping to home depot. Thanks in advance!

bubba

Tapcon fasteners. They are designed to be driven into concrete. Make sure you use the correct Tapcon bit for the screw you select. A hammer drill will probably be required to penetrate the concrete. Select a screw that goes into the concrete at least 1.5 to 2 inches. Drilling weakens the surface layer and screws less than 1 inch are prone to not coming up tight and pulling out.

Great! Thank you!