Tons of questions

So im starting my dwc already, purchased a PPM meter, PH etc. some of my questions are as followed.

Whats the deal with ppm. does this just measure the nute amount? does this go up over time while in the dwc bucket?

Same with ph, does this go up over time?

First off, make sure to calibrate your meters often. PPM stands for parts per million. If you are using tap water, it will naturally have ppms whereas RO will have approx 7-10% ppms of original starting ppm and if you add DI you will get 0 ppms. You will need to most likely use some type of calcium/iron/magnesium supplement if you use RO.
Your ppms should drop as your plant consumes nutrients unless you develop some type of algae or bacteria which would raise the ppm. Your Ph will also fluctuate based on different nutrients being consumed, the amount of aeration and temperatures just to name a few things. The best thing to do is check the ph in the morning and at night. I prefer to adjust at most, once per day, but normally can go multiple days without needing adjustment once my nutrient mix is on point.

Thanks for the info. i was wondering why my ph shot up to 6.5 when i changed it. I checked it only to see what changed and basically trying to teach myself a bit.