What parts of the help file have you read so far ? I haven't worked with character rigs for awhile, and I'd defer to animators, but in lieu of one of them chiming in I'd suggest starting with something like this. http://help.autodesk.com/view/3DSMAX/2018/ENU/?guid=GUID-ACAD407C-B079-4DAB-9DD0-6C8DC22389EF
The two poses in your screenshot don't look very different. Is the 5 frame in between not a good enough blend? So this might be over kill, but you can use the Motion Mixer to blend the two anims. Just create two XAF, then mix them together. It's a quick process when you know how, but can seem very tedious to setup on your…