When you start the game ONE PIECE Bounty Rush, you get the option to download all the data at once. Download it and start the game. In the first phase, the game will teach you the basics. You can skip it by tapping the finish button on the left side of the screen. In the second phase, you will be challenged in the 4v4 battle. You can also skip it by tapping the finish button on the left side of the screen.
In the 3rd phase, summoning tutorial will start where you will scout and pull the 11 characters. The draws will be random. You can check the drop rates by tapping the drop rate button on the top-right side of the scout menu screen. At the time of writing this post, it's like this:
After the draws, the game will send you to the party menu where you will learn how to edit the party. Then hit the home button -> enter the name -> OK. After it, you will get the login bonus, head start bonus, event login bonus, and some annoying pop-ups on the screen. You can change the name by tapping the avatar at the top-left of the home screen.
Now, tap the gift button at the top-right corner of the home screen -> claim all the rewards. In ONE PIECE Bounty Rush, rainbow diamonds are used in summoning. You will get over 150 rainbow diamonds for free. Claim them all and go to the scout menu and pull the 11 ONE PIECE Bounty Rush characters. It will cost you 50 rainbow diamonds. So you can pull three times just after the tutorial.
Now take a look at the below ONE PIECE Bounty Tier List and check if the characters you got from the pulls are good or not. If you don't like the outcome, it's time to ONE PIECE Bounty Rush Reroll.
All you have to do is rename the com.bandainamcoent.opbrww folder(add 1 to the last), then you have to clear the data -> then revert back the changes -> open the game. Hit the download all button and it will show you 0.0 MB data because files are already there. Accept all the T&C, complete the tutorial, follow the above steps until you get the top tier units in ONCE PIECE Bounty Rush.