When you install new indicator in your MetaTrader station (Place your new indicator into the MetaTrader “/Experts/Indicators” folder), if MetaTrader does not recognize new indicator you are probably add indicator while your MT station was open.
How to install new indicator properly?
Solution 1: Add new indicator before you turn on MetaTrader station, when you open MT station your indicator will be ready for usage (in “Navigator”).
Solution 2: If you add new indicator while your MT station was open, just restart (close and open) MetaTrader station and you will get indicator in “Navigator”.
If you have additional questions please post your comment I will answer you shortly.