In order to know how much your security deposit is, check the electronic lease document that was sent to your email via DocuSign or, sometimes, the property's listing.
Your holding deposit is due one business day after signing the lease. This is standard as your lease is a legal contract at the point of signing.
Your first month’s rent (prorated) is due on the day you move in.
Both payments can be submitted online via your resident dashboard. See this article to learn how to make payments online.