Learn Russian: Благодаря тому что все помогали, работа закончилась рано. - Thanks to everyone helping, the work finished early.

In Russian, prepositions like благодаря cannot attach directly to the conjunction что. Since благодаря requires the dative case, you use the pronoun то as a bridge, put it in the dative (тому), and then add что. It translates literally as "thanks to the fact that".

Is there a difference between using благодаря тому что and just потому что?

Yes. While both can be translated as "because", благодаря тому что has a strongly positive tone, just like "thanks to" in English. You only use it when the outcome is good. If the outcome were negative, you would use из-за того что instead.

Why use the imperfective verb помогали alongside the perfective verb закончилась?

The imperfective помогали shows that the helping was an ongoing background process. The perfective закончилась is used because the finishing of the work is the final, completed result of all that help.

Why does закончилась have the reflexive -сь ending?

Russian uses the reflexive ending when an action happens to the subject itself rather than to a direct object. Since the work isn't finishing something else, but rather coming to an end itself, you must use the reflexive закончиться instead of the non-reflexive закончить.