Would this be a GEDcom?
Although people do upload large family trees, my understanding is that you should only upload small pieces of the tree and then clean up the data that has been uploaded so that it will fit in with the Wikitree format.
All too often, I've stumbled across automated GEDcom uploads which seem virtually incomprehensible because the person putting it into Wikitree hasn't made the effort to integrate the information into a usable format.
My advice? Give yourself a little time to find out how Wikitree works before plunging into adding large amounts of information.
Oh, and welcome to Wikitree, Marcie1 We're glad to have you here!