Methods of programming Uniden scanners vary with different models. Some models have exceptions in their programming. In the BC75XLT model, for example, you can't unlock channels that don't have anything programmed into them; as you program each frequency, those channels unlock themselves.
To program each frequency into the Uniden BC75XLT model, press HOLD while you are in SCAN mode. Enter the desired channel for that frequency, and then press HOLD. Next, press the FUNC key, press E, enter in the frequency that you want to program, and then press E to save the frequency.
The Uniden BCD396T model has a Scroll knob for selecting options. To program conventional frequencies into this model, press the Menu button, select Program System, and then press E. Select New System, press E, select the Conventional system type, and then press E again. Select Edit Name, press E, and then press the Decimal button until all the letters disappear. Name your system, and then press E.
Select Edit Group, press E twice, select Edit Name, and then press E. Name your group. Select Edit Channel, press E, input a frequency, and then press E again. Press the Menu button, select New Channel, and follow all these steps to enter each frequency of the group. Press Scan when you are done.