From time to time there might be some lack of communication and two people end up working on the same branch, in the same file. As expected, a conflict will occur and you must decide what changes to keep in order to continue working. Versions offers a conflict solver tool that makes this job very easy.
If you’re working on a file that was modified by someone else and you save some changes, you’ll see this warning directly in Sketch
Click on it, or alternatively, try to push the changes you’ve made. You’ll be taken to this screen. Click on “Resolve Conflict”.
You’ll be taken to the conflict solver:
In this screen you’ll see the three states of the file, at the left you’ll see the changes you just made, in the center how the file was before you modified it and at the right the changes the other person made. Choose whatever side is the correct one by clicking on “Use mine”, “Revert” or “Use theirs”. At the center you’ll see how the file will look like.
In this window you can also navigate through the different artboards that might present a conflict and you’ll see a list of all conflicts at the top center of the app window. In the eye icon you can choose to see the the conflicts or changes. At the top right you'll see the options to resolve each conflict manually, or to automatically resolve all with either side of changes, you'll also find a button to reset all conflicts to take a second look to inspect them.
Once you've solved all the conflicts you'll see a green indicator saying "All conflicts resolved". Click on the "Sync" button or on the back button at the top left corner of the window.
The conflict is solved and you just need to click on “Apply Merge” to finish the process.