Your tree will not automatically populate from your uploaded GEDCOM. You must now do what is called "GEDCOMpare" where you review each person in your GEDCOM to see if there are any matches already on WikiTree. Once you have reviewed every individual and either accepted or rejected possible matches, you will get "add" buttons for the people in your GEDCOM. You will then add each person individually. You will need to "clean up" the profile and perhaps reformat your sources for each as you go.
Here's a help page you can review...GEDCOMpare...which may help.