Ante- and pre- BOTH mean before/prior/earlier.
Pre- is the commonest prefix (pre-fix!), but ante- forms the start of many interesting words. Ante-room (a room or chamber before you get to the main room, often found in palaces and tombs), antediluvian (before the flood!), and words such as anterior/posterior have that ante/post start... though they are not really prefixes here.
There's a common saying "to up the ante." The ante is the money to put down in advance in a bet. In a high stakes poker game, or in a risky situation, you can... up the ante! (bet more, or increase the risk/danger/stake)
So 'ante' has a lot of meanings associated with before/at the front/in advance.
However it is not always a prefix exactly. It is simply part of the word.
And there are some words that start ante... that have nothing to do with being before/first/earlier. How about ... anteater! This is not an ante-ater... it's an ant-eater. It eats ants.