Amplitude is the max absolute value it can take (max height a wave can have)
Frequency is how many times the function repeats on a second (how many max height waves can you see in the interval of a second, starting with a high wave)
I won’t do an ELI5 for this topic as you need to understand the basic concept, and not some fancy explanation.
It’s quite simple with a sinusoidal function representation properly explained. I can link one if you need this topic explained.