In Spanish, v and b are pronounced the same way (b) but between vowels, you don't totally close your lips to allow some air out.
Spanish e's are pronounced like the u in bury but in er and el where it's pronounced like in bed
ch is pronounced like in English
At that time,
z was pronounced dz , vs th in thick nowadays
j was pronounced like the s in leasure vs strong h nowadays
x was pronounced like sh (this is why Quixote is spellt Quichotte in French -though I wonder why there's a double t- English kept the original spelling and Spanish changed it because the sound shifted to the strong h it has nowadays -splellt j)
v was written u at the initial
you could find apostrophes, double s and ç (missing in moçuelo btw)
Spelling was not set.
This was for spelling. Grammar is another story!