Hello and welcome to the Flow forum from Point Loma!
I have never seen Seville oranges in the US, so I delighted that you are cultivating them. Seville orange marmalade is my favorite - I used to make tons of it in the UK when we lived there.
If you haven’t already, may I suggest that you join the San Diego Beekeeping Society (http://www.sandiegobeekeepingsociety.com)? They have a facebook page, and are holding monthly meetings online during the pandemic. Their talks are usually very informative and members are very helpful, although some are suspicious of Flow hives.
Hilary Kearney of Beekeeping Like a Girl is a member, and runs courses for beginners. She has a Flow hive herself. I don’t think she is doing hands-on courses at the moment, but she does offer some online training too - https://beekeepinglikeagirl.com.
If you need bees, Mark Huerta is also a senior member and sells very nice nuclei with gentle queens, but he sells out early so ask him soon. Bee Safe Bee Removal - SD County (619) 420-4546 email@example.com (mailto:firstname.lastname@example.org)
Failing that, I have had several great packages from Mann Lake:
Live bees | Package Bees with Queen - Italian - Shipped | Mann Lake Ltd.
Finally, I would like to suggest that you buy a second brood box. Our climate is prone to prolonged nectar dearths, and to survive the lean times, your bees will need space to save food for those times. You should let the bees fill the second box before you consider adding the Flow super.
I hope that I haven’t overwhelmed you, but I am glad that you joined this forum. You will find lots of helpful people here, who will happily help with any questions that you might have.