Installing Chrome extensions or add-ons will take place usually from the Chrome Web Store. Did they present an addon directly as CRX file, the manual installation is necessary. And this is how it works.
CRX: Add Chrome addons without Webstore
Actually, the manual installation of CRX files in Google Chrome has always been quite simple: open the browser, take CRX file to the browser window, done. Some time ago the googlerianische software company has changed this procedure. Now, the following steps are necessary to add a Chrome extension without Web Store manually. • First, download the CRX file of the desired Chrome addons. Now open the folder containing the downloaded extension. • Next, you open Chrome. Click the upper right of the dotted-line options Icon- will open the options menu, where you choose "Tools" and subsequently "extensions", 
• Now click on the downloaded Chrome extension and drag with the mouse on the Chrome window with the open expansion dialogue. 
• It opens a confirmation dialog of the respective Chrome Extension. Agree to the installation by clicking on "add" click. 
• A short time later, the extensions dialog updated in Chrome and the newly installed add-on is included in the list. Voila - it's done. 