Getting stuck on Challenge 2? I'm guessing the 5-letter blocks are confusing you in 2B. All that the sender has done is removed all the spaces and punctuation, and grouped the letters into blocks of five after encrypting it. It is a bit tougher because you can;t use word shapes to help you, but there are still things you can do.
1. Try to find the most common letter. It probably stands for E (or possibly T, they are the two most common letters in English)
2. Once you have found E see if you can find the word THE by looking for a common triple ending in the decrypted letter E
3. Try to guess what type of cipher has been used, Caesar shift? Affine shift? Keyword subsitution? If you guess right it is a LOT easier to crack. And given how early this is in the competition, it is more likely to be at the easy end of this list!
Do keep trying, you still have a couple of days to get your answer in.
All the best, Harry