First grow ever! Unexspected problem

i am doing my first ever grow
i got given some cuttings of a friend
i have them currently in a heated propagator.

i had them given to me in 1" cubes
i have put them in the 4" cubes and still have them in the propagator, i am going to leave them in the propagator until they have roots, is this the right thing?

when should i start feeding them nutes, i am currently giving them plant start feed?

do you really need a ppm meter (i think that what is is) or can't you just add nutes every (certain amount of days)?

rep for advice, cheers people

yes leave them in the propagator. I think u shud leave them in the 1 inch rockwool first until you see roots comin out a little from the bottom, sides. That will give them more oxygen. And also make sure that your cubes are moist enough at all times. Not soaked but moist. you should start feeding nutes when the roots are atleast a cm long, and make its at 1/4 reccommended strength so you dont burn the plants. Slowly bump up the nutrients as the plants get comfortable. Add little every week or so to see how your plants react

I grew my first set of plants by reading the directions on the bottles of nutes,then I finally got a meter for the nutes,but you have to keep your ph in check thats the biggest key to growing.

I started my seedlings in 1'' rockwool cubes, jus as the roots were about to come thru my plants went yellow and stopped growing. The first spiky leaves were tiny. I give them low dose of nutes and they sprung back to life. Next
Time i'm gonna soak RW with mild nutes so they have food straight away. Would u be hungry if u just climbed up a hill in a suitcase (jus like a seed does)