water treatment (again)

This has been one of the hardest things to grasp as an all-grain brewer. The 5.2 buffer has been an easy way out, but I want to start brewing by matching a water profile to the style of beer I am brewing. I have read many articles and sections of books about water but I am still unclear about a few things.
I agree with the statement that you should mash in, then check ph and adjust accordingly. Maybe I'm reading the wrong stuff but no one ever says in plain language what to do. I am a simple person and need simple advice.

I have posted my water report before but here it is again:

Sodium, Na 18
Potassium, K 4
Calcium, Ca 51
Magnesium, Mg 26
Total Hardness, CaCO 3 236
Nitrate, NO 3-N 0.3 (SAFE)
Sulfate, SO -4S 49
Chloride, Cl 19
Carbonate, CO 3 < 1
Bicarbonate, HCO 3 112
Total Alkalinity, CaCO 3 92

I know one of the most important (for ph) is bicarbonate which is 112. I know for pale beers I need to dilute my water with distilled water.
Most of the articles I read say to mash in, take ph reading, then take action.

What do I do if my ph is high?

What do I do if my ph is low?

The conclusions I have reached in my slow moving brain is to add calcium carbonate (chalk) if ph is low and add distilled water if the ph is high.
I appreciate the books I have read with a section devoted to water, but is there something more in depth that I can read to understand all of this? Can someone answer the two questions above?

Thanks for your advice...Charlie

Don't bother so much about water treatment, I'ts not worth it.

Your water is OK. If you make pale beers - pre-boil it to remove some bicarbonates. If you make pils, dilute it 50:50 with destilled water. If you make an IPA, add a small spoon of gypsum. Nothing more.

pH is always too high, to bring it down I use sauermalt or lactic acid.

If you like where your mineral content is but need to lower your pH, use acid. I've found that's a quick and dirty way to do that. Doesn't lower your carb level, though. Diluting is the easiest way, imo.

I use the water profile matching method for brewing and I am very happy with it, the easiest way I've found to do this is using brewing software either promash or beersmith work great. These programs allow you to enter your water profile and come preprogrammed with the profiles of the major brewing sources you might want to match, they allow you to adjust by 0.1g at a time the addition of various water salts until the desired profile is matched.

if you just want to achieve the right Ph adding CaCO3(chalk) with raise the Ph and adding CaSO4(gypsum) will lower it, keep in mind that your grain bill will also affect it. Darker malts tend to lower the Ph.
I assume you've read how to brew by John Palmer http://www.howtobrew.com/intro.html?