A funding source is the account where withdrawals are taken from; a linked checking account. A funding source does have to be a checking account, it cannot be a savings account or credit card. You can only link one funding source to your Qoins account, regardless of how many roundup accounts you have set up.
Every contribution (roundup, Smart Savings, or When I Get Paid) made by Qoins will be withdrawn from your linked funding source in $5+ increments. This means that once your contributions have reached a total of $5 or more, a withdrawal will initiate.
You will get a notification of the withdrawal being initiated, which will allow you to cancel or reschedule before the cutoff time (4:45 PM EST).