D-
To make the sign 'd', you'd point your index finger and touch your thumb to your middle finger like below:

E-
To make the sign 'e', you'd curls up all of fingers, and put your thumb over your palm like below:

F-
To make the sign 'F'- you'd make the 'perfect' sign

Hello-

To make the sign, 'Hello'- you'd put your hand to your temple and wave one time