I assume your instructions say to add the oak chips at the start of the primary fermentation. I would leave 'em in until it's done fermenting (I "ferment to dry" in the primary), where S.G. is down to 1.000 or lower. That usually takes a week or so for me, and then I would rinse and transfer them to the carboy for 2-4 weeks. The oak will be extracted before 4-5 weeks is up, but they do no harm once they are 'neutral'. By that time, your wine will have dropped quite bit more sediment, and you can leave the oak chips behind when you rack again. I would then bulk age it another 2-3 months, rack again and bottle (although a few more months bulk aging wouldn't hurt either).