Torque it to 15 in/lbs first. Close the breech bolt and use a feeler gauge/business card, or pieces of paper to see what kind of clearance you have under the bolt to the stock....keep track of this measurement for future reference. The bolt and stock should never be touching when the bolt is closed.
If you got room to torque it more you can go up to about 25-28 in/lbs in most cases where you won't end up permanently sinking the action...laminate stocks can take a bit more than the walnut. Most people find that somewhere in the 18-25 in/lb range is enough to keep the action put, not overly stress it, and get good consistency on their shooting.