I am IT literate but have never used them before. Is it easy to write information and load them up onto the website or is there specfic information that I should know before using one?
All CMS are written to be as versatile as possible. As such, they do contain HUGE amounts of functions you will never use, and require HUGE amounts of space to be loaded (Joomla is 27Mb of code!!!).
Although very versatile, they NEVER solve ALL your specific needs, and you always end-up adding functions yourself.
Their use require you to understand exactly what you are doing, or face the problems of "finding why" the CMS does not perform as expected, by going through megabytes of scripts only prefessionals with experience can understand.
Conclusion?
I have removed many CMS, from Joomla, Drupal, Miva and others, and replaced them with my own, taylor-made code.
Result?
A clear and understandable code, 100 to 200kb only, specifically adapted to client’s needs.
If you can use Joomla, you CAN write code.
And if you can write code, why would you use any off-the shelf CMS but your own????
Writing your own may take you a few days, but understanding another CMS and finding a bug in them WILL take you weeks.
Your choice!