Wah How to use So and Such.

We use So and Such to show the extreme of something.
These forms are often used in interjections.

So + adjective 

• This box is so heavy!
• This meal is so terrible!
• That movie is so boring!
• You are so clever!
• They are so lovely!
• Sara's eyes are so beautiful!

Such + adjective + noun.

• This is such a heavy box!
• This is such a terrible meal!
• That is such a boring movie!
• You are such a clever person!
• They are such lovely people!
• Sara has such beautiful eyes!

Wah How to use "So" to give explanation

You may know how to use So in many way 
Wah How to use "So + Adjective / Adverb + That"
Wah How to use "So do I / Neither do I" 

And if you want to explain why you are doing something, you can use...

• I need to get to the book store so that I can buy new arrival books.
• I'm going to the bank so I can change my foreign currency.
• Shall we go someplace quieter so we can talk in private.
• Let's go to the theater early so that we can get good seats.  
• Let's hurry so that we can catch the train.
• Lisa got a part-time job so that she could study at college.
• The money was round so that it could roll from place to place.

Wah How to use "So do I / Neither do I"

You can use So do I or Neither do I when you want to say something that is the same as others.

Positive sentence :  So + auxiliary verb + pronoun  :So do I, So am I, So have I...
Negative sentence : Neither + auxiliary verb + pronoun  : Neither do I, Neither am I, Neither have I...

For examples:

A: I am so excited.     
B: So am I.

A: I am not hungry.  
B: Neither am I.

A: John likes chocolate. 
B: So does Helen.  

A: Helen does not want to go out tonight.   
B: Neither dose John.

A: I have never been to Tokyo.
B: Neither have I. 

A: I can come the party tonight.
B: So can I.

Wah How to use "So + Adjective / Adverb + That"

So means very,extremely
It's use when you want to describe why the result happens.
The result happens because It's so..

      So + Adjective + That
      You are so cute that I cannot take my eyes off you. 
      (You are very cute that is why I cannot  take my eyes off you.) 

      This movie was so funny that I could not stop laughing.
      (This movie was extremely funny that was why I could not stop laughing.)

      The weather here is so hot that I don't want to go outside.

      So + Adverb + That
      Don drive so quickly that no one wants to go with him again.
      Micheal snores so loudly that we don't want to sleep with him.
      Wah Wasabi's website explains English grammars so clearly (that) I can understand them easily.

In general, It's not necessary to use that.
You are so cute I cannot take my eyes off you. 

Jason Mraz sings in "I'm yours" song..
"Well, you dawned on me and you bet I felt it
I tried to be chill but you're so hot that I meltedI fell right through the cracksNow I'm trying to get back..."