I watch all the Will Harlow videos and do at least some of the exercises. The ONLY Exercise You Need for Stronger Arms Over 50 is one I've done parts of but never as a whole unit.

Screenshot from video shows a man seated and holding dumbbells near his shoulders. There is also a list of steps in the exercise.

Sit down in your chair and hold one weight in each hand
Keep a straight back and point your thumbs forward
Raise both hands up to shoulder height like a bicep curl
Twist your elbows outwards
Move into a press by pushing your arms up as high as you can above your head
Slowly reverse the movements to starting position