annaepaneul chatneun de sigani geollimyeon jigwonege mureobwa.

안내판 means (information) sign / guide sign / signboard. The particle -을 marks it as the direct object of the verb 찾다 (to find / to look for).
So 안내판을 찾다 = to look for/find a sign.

찾는 is the present (attributive) modifier form of the verb 찾다. Korean often turns a verb into a modifier to describe a following noun.
Here it modifies 데 (a noun meaning a place / a situation / the act/occasion of doing something, depending on context).
So 찾는 데 is like (in/while) looking for (it) or in the process of finding it.

In this pattern, -는 데 commonly means “in doing X / for doing X” (the context is the activity itself).
So 안내판을 찾는 데 = in looking for the sign / when trying to find the sign.
This is a very common structure in sentences like V-는 데 시간이 걸리다 (it takes time to V).

Both appear in real life, but they can feel slightly different:

• 찾는 데 (with a space) emphasizes 데 as a noun meaning the act/occasion of finding → common in the 시간이 걸리다 pattern.
• 찾는데 (no space) is often treated as 찾는 + 데 anyway in casual writing, but it can also be read more like a connective ending in some contexts.

For learners, 찾는 데 시간이 걸리다 is a standard, clear spelling.

시간이 걸리다 literally means “time is taken” or “time is required.”
Grammatically, 시간이 is the subject (time), marked by -이, and 걸리다 means to take (time) / to be required.
So (X 하는 데) 시간이 걸리다 = It takes time to do X.

-(으)면 is a conditional meaning if/when.
So 시간이 걸리면 = if it takes time / if you’re taking a while.
In everyday instructions, this can be understood as “If you can’t find it quickly / If it’s taking too long.”

Yes—물어봐 is the casual imperative form of 물어보다 (to ask/inquire). It’s a friendly, informal “Ask (them).”
Depending on the relationship, you might also say:

• 물어봐요 (polite, casual)
• 물어보세요 (polite, more standard for giving advice)
• 물어보십시오 (very formal)

The -아/어 보다 form often adds a nuance of “try doing it” or “give it a go.”
So 물어봐 can feel like “Try asking (a staff member).” It’s advice, not a harsh order (though it’s still informal).

Because 직원 (staff member/employee) is the person you ask, not the thing you ask for.
-에게 marks the recipient/target of the question: ask to someone.
So 직원에게 물어봐 = Ask a staff member.
You can also hear 직원한테 (more casual) with the same meaning.

Korean commonly omits the subject when it’s obvious from context. Here it’s understood as you.
If you add it, it becomes more explicit, but it can sound unnecessary or even a bit pushy:

• (너) 안내판을 찾는 데 시간이 걸리면 직원에게 물어봐. (casual, to a friend/child) In polite settings, you’d usually switch the ending instead of adding 당신 (which is often avoided in everyday speech).