I was reading the answer to this question provided by Phil Karn.
In the answer, it has been said:
Ensure that the impulse response of your lowpass filter is shifted to the front of your time domain buffer AND properly windowed to M samples before you take the forward FFT to get the frequency domain representation of your filter. This keeps the result from wrapping around in the time domain when you take the inverse FFT. (Remember you're actually doing circular convolution when you want linear convolution.)
I know that windowing is important because of spectral leakage but I do not completely understand this paragraph.
I think in this paragraph some important points are mentioned which are worth explaining in more detail.
What does exactly "shifting the impulse response of a filter to the front of the time domain" mean?
It has been said that "This keeps the result from wrapping around in the time domain when you take the inverse FFT". Is this a result of "shifting the impulse response of a filter to the front of the time domain" or a result of "windowing"?