My question is about wp Gallery

I have three questions.

I am using the Wordpress Gallery, works great, would like to view four images across rather than three, Is that possible?

Next question in the gallery there is a place to put a link next to Alt text in the form. What link should go there, what is the purpose of the link and where would I find the link? If possible a link to display the single item in a search would be great.

I am trying to make my search capabilities more effective. When I search for an item it searches the entire site,can you search individual pages? if an item in the gallery should appear in my search it brings up the entire gallery rather than the one single item I am searching meaning I must scroll the entire gallery to find the one item I am looking for. I would like it to bring up only the one item I am searching. Do you know how to achieve that? could it be done using the link option provided within the gallery and described above?

Thank you

Mike