The output of xcorr is an array of values of how one array is similar to the other. The maximum value is when two arrays match the most. Find the place (position) of the maximum value in the array (you can look it up from the variable editor, or use built-in functions such as 'find' and 'max', I don't remember exactly). So, if your max value is at position 25, it means that the delay is 25. Also, I am not sure if it matters, but make sure to feed the xcorr function, so the shorter array slides against longer (at least it make sense analytically). Not sure if this will work, but the idea is here:
cor=xcorr(shortArray,longArray);
[~,index]=max(cor);
where 'index' should be the position of the max value as well as the delay index. So, first 25 values must be skipped from the longer array
