Hey and welcome on community forums
I will follow the nomenclature used in Genki.
So basically, there are 2 kinds of humble speech.
謙譲語I (humble expressions) and 謙譲語II (extra modest expressions).
You use humble expressions when you want to exalt someone you are talking about.
The extra modest expressions are used when you want to show respect when talking to someone, but you are not necessarily doing something to/for him/her.
Let’s assume that you are a worker at the company. You are talking to your 課長 (部長 is more important than 課長) and say:
They both mean that you showed the section manager around.
But the first has the nuance that you show respect to the person you are talking about (部長), and the second shows respect to the person you are talking with (課長).
It is more visible if we change the indirect object to let’s say まさむら、who is also an ordinary employee like you.
In here the first one is incorrect because Masamura has a similar position to you and there is no need to exalt him.
And the second is correct because you talk about Masamura, but show respect to your interlocutor.
Also, if we change it a bit, you are speaking with 部長 now:
In the first one, you exalt 課長, which might piss off 部長 who is more important and standing next to you. So its better to avoid it and use the second one, in which you exalt your conversation partner - 部長。
If you want to exalt both of them (which should be the case) and is the case most of the time, then you can go with: