Most wine ingredient kits will have fining agents (Chitosan, Isinglass, etc.) included with them. When it is time to add these to your wine it is most likely also the time that you will want to stabilize your wine (usually the addition of potassium sorbate which is also known as wine stabilizer).
It is time for a vigorous stirring! Do NOT rack your wine. Fining agents work better in "dirty" wine. Add your fining agent and then stir your wine for several minutes. Stir the sediment which has accumulated on the bottom of your carboy back up into your wine. I know! This goes against all sense of logic. The fact is that the fining agents will work much better if you do this. Instead of racking you add the fining agent and stir and then leave your wine to set for an additional week to 10 days prior to racking again.
This vigorous stirring will do something to your wine in addition to bringing up the sediment. It will drive off carbon dioxide gasses which have accumulated in the wine. If these gases remain in your wine they will prevent the fining agents from working correctly. Some recipes call this degassing your wine. Stir hard and keep stirring until the wine stops foaming. My personal favorite method of stirring the wine is to use either a Wine Whip or a Mix-Stir both of which are available on BlueStem Winery's website.