None of the engines covered by this manual use pistons with wrist pins retained by any type of clip. Press fit pistons require special presses and/or heaters to remove/install the connecting rod and this operation should only be performed by a machine shop.
All pistons will have a mark indicating the direction to the front of the engine and the must be installed into the engine in that manner. Usually it is a notch or arrow on the top of the piston, or it may be the letter F cast or stamped into the piston. This is important because pistons aren't exactly round; they are made slightly oval, or barrel shape. The reason for this is that the piston's shape changes slightly under the heat and stress of engine operation. Too, the loads on the piston are not uniform. So the piston is designed with a slight offset and in a shape that works best when the engine is running. This reduces running friction and a cold-start noise called "piston slap." The pistons absolutely must be installed in the proper orientation or you will fail the engine.