No DHCP Server

If you are one of the rare users that have no dhcp server, you might have trouble connecting the server with your network. Normally the DHCP is connected and it tells you which IP and gateway and netmask to use. Without it, you have to enter them manually. If you have a wifi network you can just add an additional ip address and enter gateway manually and are done.

If you only have ethernet, that will not work. In that case you need to connect to the raspberry using the access point which must be enabled (and is enabled by default). Best use a laptop and select the raspberry AP to connect to. Then open remote desktop on ip or create a ssh connection to the pi. After login open a shell if you are using the remote desktop. In the shell you simple enter:

sudo nmtui

It will give you a text based gui to configure the network the way you need it for your network.