Welcome to the freshwater world!
A 30 gallon isn't big enough for any shark. You would want 50-55gal min to keep 1. In a 30 you can keep a single angel. You would want bigger to keep a pair. You could happily do the single angel and some other fish however. Do you have any other fish that interest you. There are really a lot of options
Do you know what type of filter it is? GPH, brand or anything? Are you planning a planted tank or just using fake plants?
as for cycling there are some great articles on the site
here is one for fish in cycling
Fish-in Cycling: Step over into the dark side - Aquarium Advice
and this for fish less
The (almost) Complete Guide and FAQ to Fishless Cycling - Aquarium Advice
both have their pros and cons. Read them through and see what would work best for you and what you plan to stock. Some fish are too sensitive to survive a fish in cycle too so that will weigh in.
You certainly came to the right spot for help.