how do I allow people to check more than one option

If you're using simple checkboxes, just need to use a checklist. Just put the items and users can check all they want.

And this is how it likes:

If this is not the problem you're having, please, just post it. More information could help.

If you are using a radio button field, these fields are used exclusively for selecting only one option.  Using a checkbox field will allow for multiple selections.