What paper work do I need to enforce a lien in Colorado?

We are a roofing company that sub-contracted roofing work on a commercial project from another roofing company. We supplied labor only. The property owner has paid the contractor, but the contractor will not pay us. We have already sent the Intent to Lien to the contractor and the property owner and still refusal to pay. We filed the lien with the county court and they have been sent a copy. The contractor and the property owner still refuse to pay. What paper work do I need to enforce the lien and start the foreclosure process?