Licorice has a distinctive flavor, similar to anise or fennel, but with a pronounced additional sweetness. It’s used in gins for both its flavor and for the sweetening effect.
Can be a strong, spicey (heat) botanical so err on the light side, try 0.5gm per litre.
Check out this link for some info on ratios and some recipe ideas. https://www.lovebrewing.co.uk/guides/gin-recipes-using-botanicals/