I need to put an audio and video input on Sharp TV, it only has RF input (ant in)

Usually in this case, an RF modulator (you can use a modulator from dendy)
Here is an example of a modulator circuit



The modulator consists of a mixer / video modulator on the transistor VT1 and a subcarrier of the sound generator on the transistor VT2. The signal from the crystal oscillator on the processor board (26, (6) MHz) is fed to the base of the transistor VT1. The VT1 emitter receives a video signal and a signal from the subcarrier of the sound generator. The TV output signal is taken from the VT1 collector. The audio signal arrives at the VT2 base, modulating the oscillations of the subcarrier generator in terms of amplitude and frequency. Steady image reception is possible at several frequencies, multiple of the frequency of the crystal oscillator. The greatest power is accounted for by the first channels of the meter range, one of which is tuned to the sound subcarrier generator.

And here