Learn Russian: Этот соус — для мяса. Мы готовим его без соли. - This sauce is for meat. We are cooking it without salt.

The preposition для (for) always requires the Genitive case. Because мясо is a neuter noun ending in -о, it takes the ending -а in the Genitive, becoming мяса.

How does the word соль (salt) change to become соли after без?

The preposition без (without) also takes the Genitive case. Соль is a feminine noun that ends in a soft sign (-ь). For these nouns, you drop the soft sign and add -и in the Genitive singular, making it соли.

Why use его (which usually means 'him' or 'his') for a sauce?

In Russian, you must use pronouns that match the noun's gender. Соус (sauce) is a masculine noun, so 'it' takes a masculine pronoun. Here, it is the direct object of the verb готовим (we are cooking), so it goes into the Accusative case. The Accusative pronoun form for masculine nouns is его.

Why is there a dash (—) between соус and для?

In Russian, the present tense forms of the verb 'to be' (am/is/are) are almost always left out. The dash acts as a visual stand-in for the word 'is' and marks a slight pause in speech.