When you are writing, words are grouped together ... Someone really should look into that. Anyway, sentences have basic rules. They always start with a capital letter and end with punctuation ...

We speak differently than we write. For comprehension development, children need exposure to syntax common to both.

If you put a bossy verb at the beginning of a sentence, it turns it into a command ... You should also use commands when you are writing instructions telling someone how to do something.