Learn Italian: Lui scrive un libro, ma non legge molto. - He writes a book, but he does not read much.

These verbs come from scrivere (to write) and leggere (to read), which are regular verbs ending in -ere. For these verbs, the 'he/she/it' form is made by taking off the -ere and adding -e. So, lui scrive means 'he writes' and lui legge means 'he reads'.

How come the Italian sentence just says non legge instead of using a word for 'does'?

In English, we use helping verbs like 'does not' or 'don't' to make a negative sentence. Italian is much simpler! You just put non directly in front of the main verb. Non legge literally means 'not reads', which translates perfectly to 'does not read' in English.

Will molto ever change to molti or molta here?

Not in this sentence! Here, molto is being used as an adverb (a word that describes a verb) to mean 'much' or 'a lot' about how he reads. When used this way, it never changes its ending. It only changes endings to match masculine or feminine words if it is describing a noun, like molti libri (many books).

Is the word lui required at the beginning of the sentence?