We've done this since it's non-chemical: https://www.hometalk.com/8370211/cornmeal-the-easiest-way-to-get-rid-of-ants hope it helps.
I use a product called 'Terro'.
I also use terro. Comes in spray and liquid ant bait traps. Works great. Reasonable price. I buy mine at lowes.
Nothing works like Optiguard. Terro takes much longer. Optiguard gel works as an AMAZING attractant and takes the poison back into the colony to kill the queen. It is a little pricey but the results are like nothing I have ever seen. Terro....meh.
You only need a couple of BB size drops of the gel in their path and by morning....all gone.
Inside: Diatomaceous earth spread so they come in contact. Seal and caulk any entrances.
Outside: Pour boiling water, Jiffy corn muffin mix, or sevin on the the mounds.
Lots of information here: https://www.craftylittlegnome.com/how-to-kill-ants-with-borax-make-diy-ant-trap/
Hi Samira - Those little buggers are relentless, aren't they?!? This is the most effective method and all-natural spray DIY that we use with ants. It's best indoors, but will also work outside with more frequent applications. It's even been featured on Hometalk! Hope this helps! Hugs, Holly
PS - We have a FREE eBook with recipes for all of my homemade and all-natural cleaners. You can download it here --> https://pinkfortitude.com/thank#GreenClean