Haven't been paid in 3 weeks
A Colorado Statement of Mechanics Lien form can be found on the Levelset Colorado Payment Resources page. There are two forms, depending on whether your role on the projects was a direct/general contractor, or a subcontractor or supplier. Note though, a Notice of Intent to Lien (NOI) needs to be sent to the property owner and the GC at least 10 days prior to filing your claim. A Colorado NOI form can also be found on the CO resources page.
Good luck!