A-1 -> What the questions:

1 -> How to installation?
A -> Copy EnemyAlert.net.dll, EnemyAlert.ini, and the PD2Blips folder to your "Grand Theft Auto IV/scripts/" directory.

2 -> What description?
1 -> Enemy Alert blips enemies and/or their vehicles on the radar just like in GTA V.
You can also blip them on screen if you use PD2Blips: "http://www.gta4-mods.com/script/pd2-blips-f28413".

Enemy Alert.
For: Grand Theft Auto IV.
BY: InfamousSabre.

Version "1.0".

Read the License, please.