Learn Turkish: Bir dilim ekmek ve bir dilim peynir. - A slice of bread and a slice of cheese.

In Turkish, when you use a portion or measurement like dilim (slice) or bardak (glass), you just put it directly before the noun. You don't need a connecting word like "of". It is literally "one slice bread".

Does bir mean "one" or "a" here?

It serves as both! The word bir is the number "one", but it also acts as the article "a" or "an". So bir dilim translates perfectly to "a slice".

This sentence has no verb. How would we use the current lesson's word yok with this phrase?

This phrase is currently just a fragment, like an order at a cafe. To say "There is not a slice of bread and a slice of cheese", you would simply add yok at the very end: Bir dilim ekmek ve bir dilim peynir yok. In Turkish, words like var (there is) and yok (there is not) act like verbs and come at the end of the sentence.

Is ve the only way to say "and" in Turkish?

ve means "and", but native speakers sometimes drop it in everyday speech when listing things. You will also learn a suffix later (-la or -le) that means "with" and often replaces "and" in spoken Turkish, but ve is always understood and perfectly correct.