Make them yours and edit them
Right-click the Shared dot phrase library that you want to edit > click Duplicate > change the Name in Group Settings
Go back to the Shared library Group Settings and disable ☑ Include in Inline Search. Otherwise every time you search for dot phrases you will have two set of options to choose from.
Your new created library will not automatically update with new dot phrases. But you can always check out updates for new and enhanced dot phrases.
Create new dot phrases
TextExpander refers to them as Snippets. Ensure you select your own library. On the left upper corner click ＋ > on the Content (white box) write the text that you want to insert > write a creative Abbreviation > write a descriptive Label.
When you type the Abbreviation (sig in this example) the string of text will automatically expand into the content of your dot phrase / snippet.
Since you have a 1,000+ dot phrases, some times it is easier to find the by using InLine Search (Ctrl or ⌘ + ／). This is where you will see your dot phrase Label. And that is why it is to put descriptive keywords that will facilitate finding the right dot phrase.