Just moved into a new build house with no backyard landscaping done. I racked the yard to remove all the rocks and debris left behind, followed by a tamper to flatten yard enabling cleaner visual of slopes. After 2 weeks, weeds started to grow so I thought of pulling them with a weed extractor instead of using herbicides. I'm planning on putting top soil to prepare for sod in a few months. Is it beneficial to pull the weeds out and or kill them with herbicides should extraction not work? Lawn work and gardening is very new to me.

Welcome to the site!

If you can keep with them, I would just pull the weeds. It would also help if you put a general location in your profile.

If it's going to be a "few months" before your sod goes down, first of all, DO NOT put rich topsoil down. That's just an invitation for weeds! Hey, check out this nice rich place to grow out of control over here!

Second, I think you have two choices to keep the weeds in check, realistically.

(1) spray occasionally (once a month should do) with a broad-spectrum, short-acting herbicide (traditional RoundUp or the like)
(2) cover the yard with plastic so nothing can land and what's under it will be cooked to death in the summer heat (after pulling what you can right now)

(2) would be more appealing to me, but I don't know how big your yard is. A very big yard would be quite difficult and expensive to cover.

Why in the world would the builder not complete the yard in the spring if they were delivering the home in late spring?

Size of lawn?

Depends on type of weeds; is any of them spread by rhizomes, if you do not poison them , pulling them will increase number.