Some background in Linear Algebra and calculus will be really helpful.
If you want to implement backprop from scratch just look at the segment around https://youtu.be/I2TfdXfSOfc?list=PL05WXsDr_SWRGcuy5LA5eNjCq...
He explained really well how you can automatically get the derivation without going through painful calculation. Also i will suggest you to stick to the class as second half contains less maths and more fun techniques kind of like lego blocks :)
if you just want use neural net in production I highly recommend using something like theano/ keras