To be honest,it is a little complex.Here I can only express my understanding to you.
“这样”means 1.like this/this way eg.这样,你来吧。
2. To describe something eg.这样大的石头他还是头一次见过。It is the same as“这么”
“这个”means:this or this one.It refers to human or object.
“这”is a pronoun.
“这是”means:this is.Its construction is subject+verb.
You'd better find a Chinese-English dictionary to carefully read it.Hope this can help you!