First fermentation must have stopped. Otherwise the CO2 gas will keep on taking particles to the surface of the wine and therefore the wine will remain hazy. So when the fermentation has stoppen wait a couple of weeks to make sure it really is stopped and then add egg white to clarify the wine.
So be carefull with a wine that is low on tannine.
Mix the eggwhite with a bit of salt to have it fluid, but not let it foam.
When it foams it will float on the surface of the wine and it is of course meant to work IN the wine.
For a 3 gallon batch use 1/4th of an egg.
If you want to work sterile use dried egg-white available in cooking shops.