First of all put a bucket under the trap. Now use your hand to loosen the handle of the PVC type trap. Loosen both the two plastic nuts on the ends. Remove the nuts that are holding to the drain pipe. Now when you remove this trap from the drain pipe a little dirty water comes out of it which gets collected in the bucket. Now check the trap for some hair and other clogs. This you have to remove and clean it out completely. Also check the drain pipe outlet for removing any hair or other clog. Now check the portion that connects to the wall. Open the nut and remove it. Clean out the clog from it. Now disconnect the linkage that controls the link stopper. Remove the drain plunger and easily clean out the hair and clog from the drain assembly. Clean out the drain plug which has the most of the clogs attached. After cleaning out all the parts fix all the parts loosely and then tighten the screws. This whole process shall take around fifteen minutes. You only needed adjustable pliers for the steel pipe. That's it.