It's time for some inbound rules. We currently have four lines on the analog line that we can direct to specific extensions.
The first one we will create is for any call coming in on line 4 to my extension. Click the Create DID button on the top toolbar:

First, we give it a name. Then in the DID/DDI number/mask field, we can put a "*." This tells 3CX to use this for any call. Now we specify line 10003 in the for port identification field.
Next we tell it where to direct the call which, in this case, is extension 100. We want this to happen outside of our office hours, so we can check that box as well, as shown in the following screenshot:

Simple enough, right? Let's create a better one—this rule will inform me that my wife is calling, avoid the receptionist, and go right to my office.
Create a new DID. Now instead of the "*" in the DID mask field, we enter the phone number that we want to use as a filter and apply this to the main line. If it's after hours, I'd...