"Felmegyünk az étteremhez."

Translation: We are going up to the restaurant.

[sherm0]

what is wrong with we are going up to the restaurant? and what would be wrong with we are going up toward the restaurant?

[Arcaeca]

"we are going up" should be accepted - if not, report it - but IINM your second sentence would, well, require a word for "toward" - namely, felé, which isn't present in this sentence.

[sherm0]

but doesn't the hez connote "toward?"

[vvsey]

No, it does not. "Toward" is "felé".

[JohnWeber786406]

If you are going top down in the tree, the "felé" postposition has not been introduced yet. The question I have is how a seemingly general verb conjugation "felmenni" could mean "going upstairs" - does fel imply rising elevation?

[jzsuzsi]

Yes, "fel" means up.

"Felmegyünk az étteremhez." is a bit strange, but it makes sense if the restaurant is upstairs or if it's at the top of a hill.