Hi Mariam, bitmek means end but bitirmek means finish. So these are totally different.

Tik is no meaning alone but a form of "den sonra" means "after doing something"

For Ex:

Yaşadıktan sonra After I live

Geldikten sonra After I come

Ağladıktan sonra After I cry

Güldükten sonra After I laugh

Evimden sonra After my home

Bittikten sonra tabi ki gelebilirsin.  After it ends, of course you can come with us.

Bitirdikten sonra After you finish

Hi Mariam,

If you talking about flats/houses.

"bitidikten sonra" means after construction complete.

"yerlestikten sonra" means after move to this apartment/house.

So this two different words group point different times.