The first step, which has to be taken to remove the exhaust manifold is to disconnect the cable coming out of the negative terminal of the battery. Lift the front of the vehicle and place it on jackstands; then, remove the lower splash shields. Soak the bolts and springs which hold the exhaust to the manifold in penetrating oil, thus wait for some time to allow the penetrating oil to penetrate, remove the bolts holding the front exhaust pipe to the manifold then separate the exhaust from the manifold, be careful not to damage the oxygen sensor. Lower the car and unbolt the lower exhaust manifold braces, and remove oxygen sensor connectors. Now in the engine compartment, the upper heat shield that lays on the manifold will have to be removed while the lower does not. Secondly, the two bolts, one of which is part of the oil dipstick tube mounted on the crankcase stiffener and the second is the exhaust manifold support bracket bolt while the nut is also from the same bracket, should be removed. Remove the manifold on the 
Cylinder Head by unscrewing the nuts and depressing the manifold from the studs on the head, and remove the gasket. For installation, you should scrape the mating surfaces of the manifold + cylinder head and if the gasket is leaking then you should check the warpage of the said parts. Place another gasket over the cylinder head studs, put the manifold in place, and screw the mounting nuts, starting from the inner ones. Replace the remaining parts in the reverse order and start the engine and crank it to look for exhaust leakage.