I know I can do this using javascript or php, but I’m getting used to how expressionengine codes it code is a little confusing.

I have a very long list of items that I want to collapse by default and only let users see the content if they click expand.

Example
List of Items:
[-Manual 1
-Manual 2
...
]

Can this be done using expression engine? I wanted to put the code in a weblog entry.

That’s definately a Javascript job, eg http://docs.jquery.com/UI/Accordion or http://docs.jquery.com/Tutorials:Basic_Show_and_Hide. Make a custom entry field for the list contents, add the relevent code into your template and apply the JS show/hide function to it.