For your DNA: On the upper right of your page there is an active button "Add". The first item in the drop-down box is DNA - click on that and follow the instructions to enter your DNA test information. We do not upload raw DNA data - just the test info.
For your GedCom: One of our mentors created a tutorial for the [https://www.wikitree.com/wiki/Space:Current_GEDCOMpare_Process GEDCOMpare process] that others found very helpful. It is suggested that you start small - create a GedCom of about 50 people, get those through the process and then do another maybe a bit larger. It is easier to clear smaller numbers and work through your tree that way.
I hope all of this helps and welcome to WikiTree!