Weave back into the first section of row 2. Come out of the point bead in that section. This is the row you need to fit the marble into the netting. You can add it at any time. I like to add it right away to mold the webbing around it.
Some people like to wait until the last section.
You decide what is comfortable for you. Go through the next point bead. Pull the thread tight after you have added the last B bead. Re-reinforce by going around the ten beads that make up row seven. End coming out of an A bead.