Using "If" statements or commands in VBA

I need help with the proper formatting and structure for using an IF statement in VBA to get it to write out certain numbers and values in a cell itself.

I have ZERO experience in coding, in any form, so my wording above might be nonsense-able. So i'll just explain a bit more what i need.

I need to assign letter grades based of percentages using a macro that will work one line at a time. So if the % is 73.5, I need to have the cell next to it read "C" when I use the keyboard shortcut I assign in the macro and have that work no matter what the % is. I know I need to use "If/Then/ElseIF" format, but I simply cannot figure out how to properly type out the command