To set up a PPPoE connection on a MikroTik RB3011, first access the MikroTik RouterOS via Winbox or WebFig. Navigate to the "Interfaces" menu, click on "Add New" and select "PPPoE Client." In the PPPoE Client settings, specify the "Interface" to be your WAN connection (such as Ether1) and fill in your ISP-provided username and password. Make sure to enable the “Add Default Route” option and set the appropriate MTU and MRU values as advised by your ISP. After configuring, click “OK” to apply the settings. Finally, check the "PPP" menu to ensure the connection is established and has an active status.