target PPM is gonna depend on a whole lot more than a basic guideline, and it's something that just requires a little hands on practice.
First things first, you need to know the EC of your tap water to work out whether you need an RO system for your water and to see how hard it is, personally I'm happiest with RO as I know exactly what my plants are getting.
A root stim is hugely beneficial for hydro, silicon can help hugely with problems like damping off and I would definitely recommend it, calmag may be required depending on your water. Then it's your choice of normal nutes to go along with.
I highly recommend getting everything you may need - nute mix, calmag, silicon, ph down (silicon works well as ph up) then keep a careful eye on your plants, they will tell you what they need, sorry for linking to another 420 site, but this is the guide I've been using to identify what's up with my babies
https://www.icmag.com/ic/showthread.php?t=231387, don't be too afraid to experiment your plants will tell you VERY quickly if there unhappy, a quick flush and new res and you should be back on track a little wiser than before.
Dive in head first, start off with seeds you don't mind losing, within a couple of months you'll be adjusting those nutrients as second nature. Another thing worth considering is how you are going to start your seeds, hindsight has taught me to start off with RW plugs, then transfer the plugs to grow cubes once roots show, then once roots show through the grow cube place it in your medium. FEw tips using RW, Never squeeze them - this breaks the structure and prevents airreaching the roots, shake off excess water with a few hard flicks of the wrist. Don't forget to soak your cubes first in a ph balanced no nute solution for at least 6 hours, then shake and soak in a mild nute solution with a touch of silicon and root stim at full dose (root stims like rhizotonic are almost impossible to cause nute burn from)
Once you have those basics down you can start supplementing your feed in different ways.
If you want a little more guidance on your nutes then get yourself a growell catalogue, it has an excellent feeding chart for all their different nute mixes in the back, going from seedling through to flower.