1. You can check encounter user guide & cadence support.
https://www.evlsi.com/viewtopic.php?f=6&t=110
2. verify process antenna check for antenna violation. verify connectivity checks for open in the design. verify geometry checks for DRC violations like spacing, shorts etc.
https://en.wikipedia.org/wiki/Antenna_effect
3. To add a cut area to an object complete the following steps:
1. Place the object in the floorplan.
2. Select the Cut Rectilinear icon.
3. Place the cursor over the edge of the placement constraint where you want to start the cut. The cursor will change to a double arrow. Click the Left Mouse Button (LMB) to start cut.
4. Move the cursor to create the cutout area. Click LMB to create the cut.
5. Repeat steps 1-4 to create additional cuts.