The black on the landing board is the ubiquitous black mould. Generally there needs to be a strong colony and abundant nectar for the bees to store in the Flow super.
If everything is fine in the brood box, including a high percentage of worker comb, coupled with a good honey flow, the bees will fill the flow frames.
Be patient, you need to adjust to ‘bee time’, if the hive is strong and building it will happen when they are ready to use the super. When you add a super it takes time to build up the bee numbers to use the extra space you have given to them.
Regards
Hi there, can you describe these bugs or better yet, post a pic of one?
And about your super, is it a Flow super or a traditional one? If traditional, what are the frames like (foundationless, any drawn comb at all?)
You can also do a search of How to get the bees to use the Flow frames & get lots of tips there, if it’s a Flow super.
Good luck & keep us posted 
Don’t be discouraged! I had to use so many pieces of advice as a new beekeeper and finally I got my hive strong enough and see some capped honey in my flow super. If it’s a new hive the bees first work on the nucleus of the hive ensuring the queen has a place to lay eggs and the babies have food to eat. When the bees are ready to store a surplus of honey they will. It took me many adjustments to get to that point but it WILL happen. Learning was all I had and it’s was not instant gratification. Don’t give up! Whoot! 
Have a read of this thread if you haven’t already: