Je is the 3rd person singular form of být (to be), so it means is.
So the structure is:
In normal standard Czech, this verb is used just like English is here. You may sometimes see je omitted in signs, notes, or very compressed style, but the full sentence normally includes it.
In this sentence, it means open: a current state.
Czech often uses forms like otevřený / otevřená / otevřené to describe a state, even though they are historically related to a participle. So here it is best understood as open, not opened.
Compare:
Because od means from, and after od, Czech uses the genitive case.
The numeral osm changes to osmi in the genitive, so:
So od osmi literally means from eight.
Because the meaning is different.
So:
English speakers often mix these up, but Czech keeps this distinction clearly.
Because Czech often leaves it out when the meaning is obvious.
So all of these can work:
Both mean the same thing here. The shorter version is very common, especially in everyday language and when talking about opening hours.
Usually, yes, if you are talking about a branch, shop, office, or similar place. By default, people will normally understand 8 in the morning, because that makes the most sense for opening hours.
If needed, Czech can make it explicit:
But in most real-life situations, context is enough.
Yes. Czech word order is flexible, and changing it usually changes emphasis, not the basic meaning.
Neutral word order here is:
You could also say:
That puts more focus on from eight.
So the original sentence is a natural, neutral way to say it, but other orders are possible depending on what you want to stress.
Because Czech has no articles.
English needs to choose between a branch and the branch, but Czech does not mark that with a separate word. The listener understands it from context.
So Pobočka could correspond to:
depending on the situation. In this sentence, context usually makes it clear which one is meant.