I have visitors at my mother´s house. thank you

Annemin evinde misafirler (ziyaretçiler) var.

If they are your visitors you can say:

Annemin evinde benim misafirlerim (ziyaretçilerim) var.

My try...

 You dont have to use "benim" here because "m" sound at the end of the word "misafirlerim" gives that meaning.You can ask when you use "benim" Answer is:

1)Bu araba kimin?

Benim.

2) Bu araba kimin arabası?

Benim arabam.

thank you gokuyum... I understood the difference.

We also use "benim","senin" etc... when we want to lay stress on them. Ex:

This is your problem not mine.

Bu senin problemin benim değil.

Yess! I thought precisely that I was in that case because the visitors were in his mother´s house but were "his own visitors"

Well there is only one way to understand it. That is to look at the sentences before it. We can only understand which expression is correct looking at the context of paragraph. If we don´t have such an option like now we should look if there is an exclamation mark at the end of the sentence. If there is not we should not use "benim" .

Thank you for your explanations and your patience...it´s not always obvious from context indeed.

Thanks again! Iyi geceler!