You won't need to disturb the water pump.
When you get the timing cover off with the motor at TDC compression stroke, here's exactly what your timing chain & sprockets should look like:
Now... if you're at TDC between the exhaust & intake strokes, the smaller crankshaft sprocket's timing mark will still be at the same position, but the camshaft sprocket's timing mark will be diametrically opposite - it'll be pointing up to the 8:00 position instead. You'll want to roll the crankshaft over 360 degrees (one full turn) if that's the case - then the camshaft sprocket will be lined up correctly again.
If the chain has jumped one tooth, it'll be impossible to get it all lined up as in the picture - the camshaft sprocket will have rotated 10 degrees per tooth jumped. It's REALLY UNLIKELY that it'll have jumped more than one tooth, 'cause once it jumps a tooth it starts running like hammered
.
So... your goal will be to get the timing mark on the smaller CRANKSHAFT sprocket to be exactly in a straight line drawn between the center of the crankshaft and the center of the camshaft. That is absolutely, positively, the position you want, regardless of anything else - camshaft, distributor, damper, anything.
At that point, the timing mark on the larger camshaft sprocket should be ALSO on that line, the straight line between the center of the crankshaft & the center of the camshaft. If it's not, the chain has jumped a tooth... but that's why we're here, and after we get the chain off we can rotate the camshaft to where it NEEDS to be if it's not there already.
So... now that we've got the camshaft positioned & the chain & sprockets off, we hang the new chain around the new sprockets as best we can so that the timing marks are pointed towards each other just like in the picture again. We put the whole rig together on the crank & camshaft ends, verifying once more as soon as they'll hang there by themselves. If we're a tooth off, it'll be pretty obvious. If we're not, we finish putting 'em on.
Once they're fully in place, we can relax about not disturbing the engine and rotate the crankshaft around to this position:
That's where we can count the chain teeth. Go ahead, count 'em in the picture - there's 15. That's exactly what yours needs to look like. If it's anything else, we've gotta' do it again... but that's what it's gonna' look like 'cause you pay attention to detail, right?
Now that it's there & verified, it won't hurt to squirt some clean motor oil all over the chain with an oil can so it gets a good start on life. It's probably already lubed when it arrives, which accounts for the condition of your hands right now... but it can't hurt to add a little more good wet oil.
That's it - chain's replaced, valve train's timed. Time to get the timing cover & fan back on.
