According to the Colorado GOP, it’s a non-binding caucus. Everyone gets together and does the preference vote–that’s either a show of hands, a roll call, or a secret ballot and the method can change from precinct to precinct. After the votes are figured out, they then vote for delegates and alternates who will go to the district conventions.
These precinct delegates will then go to district conventions–I’m not sure what the dates are for the district conventions, but I believe they all happen before May–where they whittle down the delegates to come up with the delegates that will be sent to the national convention. So, no real delegates are set in Colorado today–at least, that’s my understanding–but you’ll be able to get a good idea of the direction that Colorado will be leaning for its delegates if there is a clear winner in the preference polls throughout most of the districts.
In sum: tonight’s caucus doesn’t pledge delegates to any candidate. That happens later in the process (and later in the year). Did this all make sense? Hope it helped.