If you look up the item on the Library Catalogue you will see a Place Request button. Click this button and complete the login details with your card number and password.
You will see a message asking you to choose a collection site and then another message telling you that the item will be either available to collect from the Borrower Services Desk by 12 noon the next day (non loanable items like theses) or that you will be notified by email when the item is available to collect from the holdshelf (loanable books) .
Alternatively you can request store items on paper forms from the Borrower Services or Enquiry Desks.
During the day store request items are collected from the store on a hourly basis.