You might want to upload in a regulated way, one family at a time, 2 parents, 4 gdparents, 8 gt grandparents and with each profile entered, clean it and source it.
So, 1st profile, clean and source, 2nd profile connected and cleaned and sourced, 3rd profile connected, cleaned and sourced .... it is slower over time to be sure BUT it will prevent your throwing up your hands and feeling overwhelmed by the amount of work AHEAD of you and just walking away from the whole project. Which is frowned upon by WT.
Sources need not be extensive FIRST time through, maybe a census URL or URL of a cemetery or birth / marriage / death record, or even a person details from familysearch with the LDS ID attached such as "Robin Cutter 1829-1917 X31J-21Z" with the familysearch URL for him / her
HAVING this first time actual source will avert having the WT dropping {{unsourced}} on the profile and/or another number of other error messages which will within 2 weeks begin to accumulate in Suggestions .. and which you are strongly advised to "clear up", correct etc
Even a source such as "Burial permit, Robin Cutter, 1917, Okefenokee, Texas, certificate #3187, issued from Beersin, County seat; personal possession by <your name>" is better than no source at all