Hello & Welcome!
new shoots only need gental light, ie a 2 tubr Florscent grow light, I use a 2 tube 25 watt t5 bulb for teh 1st couple weeks , or more.
the veg cycle requires an 18 hour ON , 6 off with a Metal halid bulb. the Sodium bulb is for the bloom cycle & is 12 on 12 off.
as adding Nutes, as soon as you get 2-3 nodes of shoots , and a root system you can start to add nutrients.
start weak solution & watch leaf tips for ram horn curling ,1st indicatin=on of over fertlization, & tips crisp & browning is a more advanced state. cut back nitrogen & watch for a couple of weeks. next nodes should grow in & NOT be rams headed or browned out.
booked are full of info, but mostly You will learn thru trial & error.
look into the Lucas formule, I like & Use teh 2 part one based on General Hydrondics Bloom & Micro .
Luck,
SLAG