Replacing hydraulic lifters is pretty easy, really.
First, go to the injector replacement file and follow along to get the intake manifold out of the way.
Then remove the cam cover.
Remove the camshaft bearing caps - keep them in order! They each fit in one place, in one direction. I always like to nail 'em to a board to reduce the possibility of confusion.
Now, the right way to do this is supposedly to also take off half the front of the engine so the camshaft is totally out. But that's a lot of nasty messing around, unless you want to replace your timing belt and water pump at the same time anyway,
I undid the front cover nut things, and marked the belt and cam pulley just for laughs, and simply tilted the camshaft up at the rear and pulled the old lifters out with a magnet tool. There was just enough clearance to get the frontmost lifter out.
Then you just carefully drop the new ones in place. That's all there is to it.
Oh, yeah, then carefully torque the camshaft back down, replace the cam cover, and all the other junk you stripped out to get to it.