You can start with the base character using the blender tools I point to above. If you want to just animate the unreal base skeleton, within unreal you can export the skelmesh and use the UE to rigify to set up the character for animation.
The videos and livestreams linked on the bottom of that page will outline the process. Also, the second and third videos outline using other types of characters. Kaye uses a deer from a free pack, re-rigs and animated then imports back into unreal. I highly recommend watching the short tutorials and at least the first 2 livestreams.
If you are reasonably comfortable in Blender and follow along you should be able to set up a pipeline pretty quickly, the longest hangup I had was aligning the export paths for different assets to the correct folders in Unreal… I make animation or model edits in Blender and 5 seconds later I am using those changed assets in Unreal.
You dont have to use the rigify stuff at all, nor are you pinned down to any specific skeleton or animations… starting with the standard mannequin stuff can help speed things up, but are not necessary. Totally up to you and your projects needs.