I am restarting my project and I retargeted my Mixamo character to the SK Mannequin character but my character now has floppy arms. When I retargeted with HeroTPP, though, my character was fine.
Could anyone please give me the link to the blue HeroTPP plus animations? 
Search here.
Why not just download it from the marketplace? When you go to add it to a project it will usually prompt you to choose a version. If you choose a pre- 4.8 version you’ll get the blue guy if I’m not mistaken. Unless you mean the old-OLD, pre- animation pack blue guy. Then you could go through the Unreal Engine channel 3rd Person youtube tutorials. I think there’s a link in there for the original blue guy but, keep in mind there were like 4 different characters before 4.8. There was the blue guy with only unarmed animations, the animation pack blue guy, Owen from the Content Examples file, and the FPS demo guy. These characters are all different.
Thank you.
Now the retargeting is coming along smoothly.