Short video tutorial of Sheetmetal Extrude feature - sheetmetal from scratch.
In Creo Parametric Sheet Metal mode is good practice to begin create base shape with the primary wall feature - Extrude feature.
The cross-section for extruded wall is generally sketched as open section. It is possible to extrude closed loops too (for example: rectangular shape).
In the sketch you can include bends, or leave these bends as sharp corners and system can convert them automatically to bends.
It is possible to set configuration option smt_add_bends_on_sharp_edges (Determines if bends will be added automatically on edges with sharp geometry in the wall creation tools. Yes - bends will be added automatically. No - sharp geometry of edges will be kept.). The automatic conversion does not include sharp edges connected to existing geometry.
Note: You can set in the dashboard outside or inside radius.