i made some modling chocolate   yesterday and its too soft and i dont know how to make it more firm.

You can try mixing some fondant in it or sometimes if your kitchen is too warm, it will be soft. Sometimes when my hands get too warm, i have to let it sit for a bit and then i start again. HTH

ill try that thanks

Once its too soft there is not much you can do but let it sit unwrapped for while. I've discovered that if after the chocolate melts you let it cool to around 90 degrees before adding the corn syrup it turns out perfect every time.

I'd try warming up your batch a little and adding some additional melted chocolate, kneed it in well (messy! lol) and then pop it in the fridge to check if it's hardening up better.

I find a good test is to leave a pea-sized piece wrapped in cling wrap at room temperature for an hour, if it's still too soft to use then add more choc or kneed in some GP, if it firms up well then anything you make should firm up the same over night- if you need a more delicate piece to hold its shape well you can put it in the freezer for 5 mins, but it will form condensation on the surface after you take it out so it'll still have to sit over night to dry out :) Hope that helps :)

Easy fix. You can knead in more melted chocolate to make it firmer. Or dust with corn starch to reduce stickiness. Make sure you are working in a very cool environment. Even overly soft modeling chocolate is workable in a cold room.