Since the transaction already confirmed, there's few things you want to consider next time :
1. Make sure you set fee which is suitable for your needs (1 sat/byte for non-important TX and higher for important TX). Website such as
https://coinb.in/#fees and
https://bitcoinfees.earn.com/ should be good, however
https://bitcoinfees.earn.com/ tends to over-estimate fees for next-block/fast confirmation.
2. If you still unsure/confused, you should use wallet which support RBF (Replace-by-fee) which make and broadcast your transaction, but with higher fees.
3. If you accidentally sent TX with low-fee again and your wallet don't support RBF, you could try contact the receiver to spend the bitcoin/input to make your TX could confirmed faster.
But generally you don't need to worry about set low fees, unless time/speed is important in your case
I've never understood what these 2 lines are on
https://bitcoinfees.earn.com/I assumed the lines that contain a number are the number of transactions in a queue with that given amount of sats per byte. Is this correct?
For instance, 1-2 and then the 2 lines, 2783 in orange is number of transactions on 1say/byte and 39729 grey is number of transacting on the 2says/byte.
What I find confusing is.. why would people pay 2 sats instead of 1 when 1 is way less crowded?
Pesonally I just use whatever is in 0-3 delay so around 5 sats these days.