If you want to be an online merchant, you should not only learn ccna, but also learn ccnp.
I suggest you find a professional training school to study systematically, because network engineers mainly learn the accumulation of hands-on operation ability and experience. I participated in the network engineer training of Harbin Galaxy Cisco. After I go to work, you will understand that training is absolutely valuable, and you can't learn many things by yourself.
I wish you success in your studies!