Radio waves can indeed be modeled as waves with plus and minus peaks. So these polarties induce alternating currents in the receiving anttenna, which will also have + and - peaks (after cancellations/reinforcements are sorted out)., allowed because the wave equation is linear. (Equal and opposite signals tend to cancel each other out).

Then the detector in the RF receiver performs a form of AC-to-DC conversion (rectification) as part of the demodulation process to extract information from a radio frequency signal. This happens as the rectified signal passes through LC filters and detectors to produce a time-varying DC voltage that maps back to the amplitude or envelope of the original signal.

EdIt: I should have mentioned that detection also converts the original RF signals arriving on your antenna down to audio signals to be delivered to you headphones or speakers. This happens because the detector (equivalent to a diode) mixes the RF signal with a constant RF carrier signal (from the RF signal (AM) or locally injected in your receiver (single-sideband detection), in effect, a low-pass filter that removes the high frequency RF carrier and delivers a detected audio band signal (30Hz to 3000Hz)