I inherited this knife from my uncle. Any tips?

I inherited this knife from my uncle who passed away. He gave it to me before he passed away. He had said he used it for cooking a lot and that he'd had it for a decent bit of time. He said it was a raindrop Damascus pattern and that's about all I know about it.

I want to be able to use this knife and keep it well maintained, how do I do that? Theres a little bit of brownish residue on the blade, I'm not sure if it's rust or just gunk. I'm not sure how I would go about cleaning it. It definitely needs some sharpening. Of his things I found what I think is a sharpening block. When I look at it it seems to have two levels of grit, one on each side, but I'm not sure if this block is worth using or if it's better to get a new one.

Also what would be appropriate to use this knife for? If i use it for daily prep of what I cook in sure it's going to wear the knife out further over time, but at the same time I don't want to only reserve it for special occasions as then I will never see it.

This is my first really high quality knife and I've been kind of scared to use it. I hope that's normal. Any tips would be appreciated