Hi Daisy, I have looked as well and it seems that Microsoft has not yet added all the options into the beta. That's normal since it is still under development and not a final product.
However, I've found a way for you to make changes to the Inbox and Sweep rules without reverting to the standard version of Outlook.
Simply go to this link. The options panel of the standard version of Outlook will open. You can make your changes and the same will appear in the new (beta) version of Outlook as well.
Outlook.com options.png
You can also manage other settings for your mailbox which are inaccessible in the beta. The following is the reply from Microsoft support regarding the missing options:
This Outlook.com beta still is not the final product of this version and some features are not available as of yet since it is only trying to show the new interface of the Outlook.com program so it is normal for it not to show the other options for the mean time. If you really need to make a change to your Inbox and Sweep rules as for the moment, you can switch back to the previous version of your Outlook.com before this beta and you don't need to worry about missing the feature as this will eventually be applied to all users once the finished product comes out.