After the observation period you will be placed in Reserve Tier I. The Reserve Tier I amount is the sum of all your payments collected over the past 7 days, or the amount of any unresolved transaction disputes (that is, buyer chargebacks and claims that are still in progress), whichever is higher.
Note that you collect the payment for your transaction when you ship the order, not when the order is placed. For Reserve Tier I, this typically means we will hold the funds for an order in reserve for 7 days after shipment before allowing you to withdraw them.