How an we translate "in which".   I am trying to say "Halay is a dance in which people hold hands".  But I´m struggling as usual!  Here is my attempt........

Kişiler elleri tutarlar vasıtasıyle Halay dansı

its gonna be like this;

´´ Halay, insanların ellerini tuttukları bir danstır.´´

Thanks, but can you explain the suffixes especially the ones in red?

Halay, insanlar-ın ellerini tut-tuk-ları bir danstır

insanların = insan+lar+ın =people´s  the suffix ´´ın´´ is possesion suffix..people´s ..its done by people..it belongs to people..the people´ hands =insanların elleri

for example : the teacher´s book = ögretmen+in kitabı ...ögretmenin kitabı

the second one is tutmak= to hold  tut+tuk+lar+ı = the thing or things that they hold..

for example = yaşadıkları ev = the house that they live.   yaşa+dık+lar+ı  ev..

so here dik,duk ,dük,tut,tik,tük,tuk are the suffixes that describes the noun..its acting like adjective.

anothe example : the book that i read= okuduğum kitap = oku+duk+um kitap..here duk changes into duğ cos of the person is ´I´

the book that you read = okuduğun kitap

the book that she/he read: okuduğu kitap

the book that we read= okuduğumuz kitap

the book that they read= okudukları kitap

hope it helped you to understand..

Yes I understand a little bit more now.  Thanks.
I hope I remember it and it makes as much sense next time I come across it! 

"which" is a relative pronoun and

"a dance in which people hold hands" is a relative clause.

When translating this type of relative clause, we use -dik+possessve suffix (non-future) or -cek+possesive suffix (future).

Usually we don´t need (so drop) the preposotions (in, at, on, to, from,with):

the direction to which we are heading = gittiğimiz yön

the restaurant at which we usually eat = genellikle yediğimiz restoran

the town from which we are coming = geldiğimiz şehir

the house in which we live = yaşadığımız ev

Ifthe subject of relative clause is not a personal pronoun (I, we, you, etc) we put it in genitive case (-(n)in suffix) in Turkish:

the direction to which Ali is heading = Ali´nin gittiği yön

the restaurant at which Ali usually eats = Ali´nin genellikle yediği restoran

the town from which Ali is coming = Ali´nin geldiği şehir

the house in which Ali lives = Ali´nin yaşadığı ev

So:

a dance in which people hold hands = insanların elele tutuştuğu dans