how to install this:
ask this type question in general section .
1) at first you must download it or any other indicator or expert .
so you have : ASCTrendND.mq5
2) then paste it in your mt5 : C:\Program Files\...trader 5\MQL5\Indicators\
in each sub folder you want
3) you must compile it , for this run the indicator buy double click it;
metaeditor will open it. then press compile :
4) now in Navigator you see the indicator.
5) drag & drop it on chart.
Did you read the explanation given in the Codebase ?
answer is above : angevoyageur
sorry , i told it in general.