(Official website: https://www.perforce.com/products/helix-core-apps/merge-diff-tool-p4merge can be used as a stand alone app)
So that easy: https://www.bbsmax.com/A/amd08Enkdg/ Good!
P4Merge document:
https://www.perforce.com/manuals/v17.3/p4merge/#P4Merge/diff-merge.p4merge.html on the pop-up interface can be found via Help .