How to edit templates?

My goal is to get rid of the “Created by” tag and move the “Last modified” tag to its place. From my research this could be done, by editing the template or overriding the skin, but I have not had any success. Anybody able to provide some guidance on this?

Hi. The template is contentheader.vm, see xwiki-platform/xwiki-platform-core/xwiki-platform-flamingo/xwiki-platform-flamingo-skin/xwiki-platform-flamingo-skin-resources/src/main/resources/flamingo/contentheader.vm at 2c483c33e73b05763515eaf19d7bf8fbdda3bfe3 · xwiki/xwiki-platform · GitHub