Glad you got some help here, Ken.
I have a chart that I printed out from somewhere (?) next to my computer with just about every mark you could make. Always "alt" and then some number.
However, they use Macs where I work and I've been doing everything in Spanish for the past few months. It's even easier on a Mac. For accents: option-e. For ñ: option-n.
Learning umlauts on a Mac comes next....