going hydro how far into hydroton does plant go?

sorry if there is a thousand other threads on this i really didnt know what exactly to search for and i couldnt really find anything on this.

im going hydro from soil and i would like to know how far to put the plants into the hydroton filled net cuts and how far into the water they go. if i could get a detailed explanation it would really help!

the plants are about 4-6 inches above the soil and have been in the soil for a few weeks now.

thanks in advance!