To get reimbursed for something:
If it's a single item/receipt, just go down to the Bio Office - they'll help you.
Multiple items or a conference
For multiple or complex reimbursements (like for a conference), copy this document, fill it out, and share it with Laura (email@example.com)and Tre (firstname.lastname@example.org) in the Bio Office. You will need to share a PDF with all your receipts (single PDF) or email a single PDF to Tre. There is a line on the form to include a link to this shared PDF file.
--> SfN (Society for Neuroscience conference)
If you paid for the registration yourself, then you will need to wait until you return from the conference in order to be reimbursed. If you put the registration on a P card, then you don't have to worry about that.
As for the documents and such that you need for the reimbursement, you need proof of registration, a receipt, proof that you are presenting, and a statement regarding why your presence at the conference benefits the grant (assuming it is being paid by a grant). Once all of that is put together, you can send it over to email@example.com and Daniel Bellow (firstname.lastname@example.org) will process the reimbursement.