From the EditorToolbar you can export selected text to a new tiddler and insert a link Transclusion or macro in its place. Click Excise text (), input name of the new tiddler, and choose excise method.
*NOTE: If you choose tic the option to
Tag new tiddler with the title of this tiddler. The tag will be the draft title. If you create a new tiddler (or clone an existing one), the draft title and the tag, will be
New Tiddler. You have to save the tiddler and re-edit it to get the new title as tag.