Insert or over-type feature. I would appreciate getting advice as to how I can use the Insert

Question

I would appreciate getting advice as to how I can use the Insert feature. My Logitech keyboard has Insert and a line under it and Print Screen below the line. I have tried using it with the Shift, Alt as wel as control button alternately besides just Insert by itself but have had no luck.

If someone could write back and instruct me about the Insert feature I would appreciate your help.

Thanks.

Frank