This achievement requires that you earn 3 stars on ALL 150 levels of the game (450 total stars). Simply completing all the levels (with at least one star) will unlock the "BRAVO !" achievement. Earning stars in the game is entirely related to how quickly you can complete the lone objective of each level. In the top middle of the screen is a timer. For 3 stars, you will need to complete the level when the timer is in the green. For 2 stars, in the yellow, and for 1 star you will only need to complete the level (timer will be red). There are 10 worlds (with 15 levels a pop), and each unlocks when you earn a cumulative total of stars, the last of which being Cow Panic which unlocks at 350 stars. Initially only the first level of each world will become unlocked. Subsequent levels are unlocked by completing (earning at least one star) in the previous level.
When you start out playing the game, earning 3 stars on some levels will be quite challenging. Your goal initially should be to gather as many stars as you can easily get, progressing far enough to unlock the Far Side world (requires 260 stars). Then play through to Far Side 15. This is the best level in the game to grind coins. See the "Best Coin Grinding Method" section at the end of the Roadmap for more information. After you get enough coins, you can fully upgrade you jetpack and bat to make earning 3 stars on all of the levels very easy in most cases. There will still be a few levels that are challenging. It is advisable that you grind some additional coins to purchase power-ups when you need them. Power-ups can make very difficult levels a breeze. The two most useful power-ups for you will be "Win 8 coins for the price of 1" and "Guide the Rabbit where you want to." The former will be useful on level where the objective is to collect a certain amount of coins. The latter is useful for just about every level (especially the 15th level of each world), but is relatively pricey at 500 coins per usage.
With your gear maxed out and some upgrades at your disposal, earning 3 stars on each level becomes quite straightforward and simple. The game is relatively new and unpopular, so there are no walkthrough videos available. Even if there was, they might not be all that useful due to the precision and timing needed to complete each level anyways.