@GabbyG
If Template code looks all jibberish to you, i think even with intent to reduce costs for that non-profit site/organisation you should consider about hiring a professional or ask someone who could help you.
The fact is if you don't find your way thorugh basic xHTML, CSS and some Smarty you will be lost, not only in this System but any that is around. Only difference would be that in some systems Smarty will be replaced with PHP, XML or some other language.
Regarding understanding Smarty you should read through existing Sample Templates and check Smarty documentation
http://www.smarty.net/docsv2/en/ it is not that hard to learn or find your way through also as absolute no Programmer like me.
For your needs described above you would need few modules like:
Frontend Users, SelfRegistration, Frontend Users listing, CustomContent, Forum Made Simple (i would rather go with a forum intended system, depending on planed number of users)...