The button is set up to press in the negative direction of whatever axis you set for it, IE: Axis_Z will press in -Z direction.
If you want the button to move in the other direction than you just need to rotate the button component 180 degrees on its interactive axis. If you mean that the MESH is going the wrong way, then your mesh is upside down or flipped. I wouldn’t use negative scaling to fix that because component bounds are incorrectly calculated when an axis is flipped and a lot of small things break (like Epics vr template hands).
You can re-import the mesh to correct it.
After you build a development build you can literally just launch the UProject and use the engine like normal, the compilation is to setup the binaries so that you can do that. You can also download the pre-packaged binary .zip files and just use those, but I warn people that generally its preferable to learn to compile it yourself. With manual compilation if a new hotfix comes out and you need to work right away you can just re-compile and go, generally hotfixes in the same engine version don’t require source changes.
Hotfixes don’t always require recompilation (they aren’t supposed to), but “sometimes” they do and its better safe than sorry.
Not to mention that I add fixes and features constantly and I batch them into the .zip downloads so I don’t have to re-compile every binary every day, so the repository is generally a few days to a week or two newer and better than the downloads.