I also thought this to be complicated my first time I did it.
But isaac laid it out step by step to follow.and it really is easy to do.

First step is the ssl certificate that has to be installed on the server via the hosting control panel.
Be it either a free one provided by the host or a private purchased one.
To me that was the hard step.

Then just follow the directions given above..

As far as paths in the ubb control panel goes.
paths that have the http:// are the only paths that need to change to https://