If you've configured your WAP to act as a gateway, you will have your wireless network on a separate subnet from your wired network. In this case, you could be using infrastructure mode or ad hoc mode.
The instructions below could work in either mode. You'll likely be using infrastructure mode, so that your network is centrally administered. You can implement DHCP services by running dhcpd directly on your gateway, or by using dhcrelay to contact another DHCP server elsewhere in the ISP or corporate network that manages DHCP services for subnets.
If you're running dhcpd on your gateway, it could be that your gateway is for a SOHO. In this case, your gateway is directly connected to the Internet, or to an IP network for which you don't have control or administrative privileges. You may also be using NAT in this case, as you've been given only one IP address by your Internet Service Provider. Alternatively, you may have administrative privileges for your network subnet which you manage.
If you're running dhcrelay on your gateway, your network subnet is managed elsewhere. You're simply relaying the DHCP client requests on your subnet to the DHCP server that exists elsewhere on the network. Your relay agent forwards the client requests to the server, and then passes the reply packets back to the client.
These configuration examples assume that you have an interface other than the wireless network adapter that's completely configured to exchange TCP/IP traffic and reach any servers noted in these configurations that exist outside of the wireless network. Your gateway will be forwarding IP traffic between this interface and the wireless interface.