You don't need pics,
Your plant needed nutrients so it took them from the lower leaf. Yellow leafs have just giving up the nutrients to the rest of the plant. They are done now. Go ahead and cut them off.
You will notice new growth a light green in color and most all of the leaf tips will be pointing up when you plant is healthy. don't over do the nutes. use half what recommended. If you want move up slowly over a couple weeks time but half is all I ever use.
Good Luck.