I do it this way, others may do it differently.

1. Time the action doing it yourself. say 1 second to lift hand and 1 second to move it a but.  2 seconds total at 30 fps is 60 frames

2. Position the figure in a neutralpose at frame 1 and keyframe all actors.

3. at frame 30 position figure with hand raised, and any other pose changes and keyframe it.

4 at frame 60 next pose, hand moved a bit , maybe head tilt , keyframe it.

5 run the anim in preview and see where its rough.  We want the nad to stay in place for a bit so go to frame 20 , and copy paste the hand and arm keyframes from frame 30. Also past them to frame 40.

keep adjusting and adding new keyframes till its smooth enough.

I would allow 30 minutes for that , you might take a couple of hours, but thats ok.

If you have enough keyframes start using the graph editor to check how smooth a curve you have and make small adjustments in that.