Here are some videos describing convolution and sampling.

CONVOLUTION

Convolution is a linear concept describing the system output in terms of the input its interaction with the system.  The system response is usually described in terms of a given input like an impulse.  The impulse response is the system output with the input given as an impulse.  Any input signal can be described in terms as an infinite set of impulses that are summed together.  The overall system response to any input is the summation of the responses due to each impulse at the input.  So for a linear system,  if you delay the impulse by t0, then the impulse response is also delayed by t0. Say you double the input amplitude, then the output will be doubled in amplitude.   Keep the above points in mind when viewing the videos below.

SAMPLING

Bottom line:  The Fourier Transform of the Sampled Signal for a given input X(f) consists of multiple spectra of the original signal.  The video below uses convolution in the frequency domain to show this.

Above unedited videos are in pre-production phase or very raw form.