While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
I would suggest contacting who is doing the training and explain your limitations. Hopefully they can accommodate you but I'm certain they would appreciate some advance notice. "Tactical training" is a little vague as to what you will be doing.