I’m most familiar with the Sluggo brand of products and have had good luck with them. I just sprinkle their organic slug bait on the soil in problem areas and that’s all there is to it.
As with all products, be sure to read the label directions. Remember that more is NOT better! Read how often you can apply the slug bait and at what concentration.
You can find organic slug bait at garden centers, some hardware and home stores, and online.