Your first step should be to create some folders (e.g. by assignment), this will allow you to organise your work more easily. You can easily drag and drop references into folders too.
When you first go into your account you can change the view to make your references display in the Harvard Solent style by clicking on Normal View in the top right hand corner of the page and changing this to Citation View, making sure Harvard Solent is selected.
It can be useful to change the view to full view if you are working on a dissertation or systematic review as it also displays the abstracts of articles you have imported. Your selected referencing style will not be affected.
RefWorks defaults to Harvard Solent if you need to use APA 7 you will need to change the style.
Click on the cogwheel by citation view
Enter APA 7 in the search bar - select APA basic. This will now be your default style. You can switch back to Harvard Solent if you wish