Complex sentence: Grievous effectively styled them to resemble his comrades by presenting them with the garbs of the native warriors of Grievous' home planet Kalee and training them himself in combat techniques after erasing their original programming.
Split into simpler sentences: Grievous effectively styled them to resemble his comrades by presenting them with the garbs of the native warriors of Grievous' home planet Kalee. He began training them himself in combat techniques after erasing their original programming.