If you have a gedcom of your family line, you can upload it to wikitree. Secondly, You can add family to your personal profile by clicking on the "add" tab located on the right hand side of the page.
There you will find columns for adding family or a new person. Start from your parents and work down from there. A new page will open up with a form. Fill this out and create a new profile. There may be other profiles with the same name,check to see if they are the same by the date or location. You may or may not find a match. If you do, you may have found a missing cousin or relative. The key word is collaberation. That is what wikitree is all about.