As this is conditional formatting, you don't need the IF bit. Select
B1, then Format | Conditional Formatting and choose Formula Is rather
than Cell Value is. Then enter this formula:

=(A1="h")

then click on Format, Patterns tab and choose yellow as the background
colour and OK your way out of it. Excel often puts extra quotes in the
formula, so if the background colour does not change when you have H in
A1, then check the formula again and edit if necessary - it should be
exactly as shown above.

Hope this helps.

Pete