Create a report based on a specific user id number

[nikit]

I want to create a report based on a specific user id
which I pick to the show me a total of all payments made?
I am able to create a report which sorts the ID, but it
shows all of them and not just the specific ID that I need.

Also, I would like to create a combo box that would allow
me to choose more than one item...I know how to create a
combo box to allow to choose one item, such as
male/female, etc...but I need some way to track days of
the week...for example if you had a school and wanted to
track what days of the week a student was enrolled (M, T,
F)...how can I choose multiple values and have them stored
in the DB?

Thanks for you help in advance.