How do I load a separate list to study? For example I'm learning list 1 and my son is list 2.
How do I load just an individual list for my son? When I click on study, it loads all characters from both my list and my sons.

Adrlly, have you ever tried it with setting up a group for both of you (I assume, you have 2 accounts)? Just go to the home page and look for group. Once you are in there, it will tell you, how to proceed.
Next step: assume, you have 2 lists, myList and sonsList. Open myList (from study or from vocab lists), go and open the relevant section. On the top you'll find "word actions". Select all the words which you want your son to study, select copy to list from words action and copy them into the sonsList.
Last step: go to sonsList, on the master page of the list, you'll find on the left side "Group Assignments" (but only, if you have created at least one group) and assign this list to the group. Now your son can see this list within his account.
Then you can keep adding more and more items to this list, create new sections, etc. The list is under your control, but your son can learn it. The only thing which doesn't work is assigning of example sentences, this kept on an account only basis and must then be done twice.
Hope, that helps.

On the "study" page there should be a button that says "Study A Single Vocab List". Click that and then click the list you want to study~