[I want a guide to tell me what should I do next, because I want to keep it even if I did it wrong..
You are not growing a bonsai, you are growing a tree. Follow the guidelines for growing lemons:
www.gardeningknowhow.com/edible/fruits/l...row-a-lemon-tree.htm
Do not try to make this a bonsai now. First, get the trunk fatter, the plant very healthy and growing, then start thinking about the next step.
OK thank you, I'll just wait now and let him recover and grow before doing anything further.
