Logical steps to learn while converting css/html5 to a wordpress theme.

Hello, this is my second post, and i want to convert simple html5/css to a working theme, and if someone can suggest me what you consider neeeded to learn programming my first theme, where to get started without previous theme design. is there a good tutorial??? please suggest it, is it there a good book, please suggest it to me.
Thanks in advance for your good predisposition counting that i am a newbie on the topic.
Salutations.