It seems like you have provided a key phrase 'Riftbound instal the new for mac' along with some text related to video games, operating systems, and software installation.

Based on the text, it appears that you are looking for information on how to install Riftbound game on your Mac.

Here's what I can suggest:

1. You can download the Riftbound game from its official Steam page or other authorized sources.

2. Once downloaded, ensure that you have a compatible operating system ( macOS ) and necessary software requirements (e.g., Steam client).

3. Follow the installation instructions provided by the developer or the installer.

As for the text about clean installations and file migration, it seems like you're considering whether to perform a clean install of your Mac's operating system or migrate files from an old Mac to a new one.

If you need help with cleaning installing your Mac or migrating files, I can provide general guidance. However, please note that specific instructions may vary depending on the version of macOS and other factors.

Would you like me to elaborate on either of these topics or is there something else I can assist you with?