You need many think for build your own corpus. First you should have a strong desire in your mind to build it, should work hard. When we speak about the technical part, that you may have to search in google since i have no more information on that
Before you start to build your own corpus, you need to decide what kind of
corpus you want. There are two main kinds of corpus. The
first is a corpus of a specific genre of text, for example, academic articles,
business letters, and newspaper feature articles. The second is a general
corpus which includes texts from a wide variety of different genres.
Use MS Word to put every sentence in your text on its own line. A quick and dirty way to do that is to Find-&-Replace every period in the text with a paragraph marker. (See Edit menu.)
Do the same thing with question marks and exclamation points.
Convert you text to a table. (See Table menu - Convert text to table) Your objective is a single-column table, with each cell containing one sentence.