Got a lot of stuff I have to get(other meters and stuff and plan to upgrade to a bigger system).

Questions

1.How much of the nutes that comes with it do I use.It's supposed to be a 6 month supply but I've read in other posts that you should only use certain amounts at certain stages of growth.

2.What brands of nutes should I get(I'm just using the packs that it came with to get a feel for the system) or are recommended and where can I get them.

3.I have a ph meter and it comes with two bottles of calibration solution.How do I go about using them?It says submerge it in the solution but there isn't enough in the bottles to submerge it to the line.Do I add it to water or something or what?

4.Any particular brand of PPM meter i should get?I hit ebay and I see them from $12-$700

I'll add more questions if I come up with any.
Thanks in advance.