FIR Filters and moving average filter Fir filter confusion

I am trying to get some knowledge about FIR filters. According to above link FIR filter is just the convolution of a sampled input signal to impulse response of a filter. I have done some research and according to some texts FIR is the same as calculating the moving average of the input samples and there is no talk about impulse response. It seems if we take the moving average we can create a filter.

I would appreciate it if someone could help me to understand FIR filter . According to tutorials here we make FIR filter by just delaying the samples .https://greatscottgadgets.com/sdr/10/
A FIR filter is (similar to, or) just a weighted moving average filter, where (unlike a typical equally weighted moving average filter) the weights of each delay tap are not constrained to be identical or even of the same sign.  By changing various values in the array of weights (the impulse response, or time shifted and sampled version of the same), the frequency response of a FIR filter can be completely changed.