Select the object in Object Mode
Press Tab to enter Edit Mode
Select the faces you want to UV map
Press U to open the UV Mapping menu
Choose an unwrap method
Use Unwrap for marked seams
Use Smart UV Project for automatic mapping
Use Cube Projection for box-shaped objects
Use Cylinder Projection for cylindrical objects
Use Sphere Projection for spherical objects
Use Project From View for view-based mapping
Open the UV Editor workspace or panel
Inspect the UV islands
Move, rotate, and scale UVs with G, R, and S
Mark seams with Ctrl+E and choose Mark Seam
Unwrap again after marking seams
Pack islands if needed
Save the UV layout if needed