Laurence, there is no alternative for Flash. If you don't have it, then as you've noticed, you're going to miss out on a lot of useful things on the web.
The Flash Player security problems only really apply to users who are running outdated versions. If you're running Windows 8/10 and are using Internet Explorer or Edge then Flash updates are installed automatically so you don't need to do anything to keep safe. Likewise, Google Chrome uses its own version of Flash and that too is updated automatically. For other browsers (such as Firefox) you should update Flash as soon as you receive a prompt.