Welcome to the Apple Support Communities.
Congratulations on the new Mac! To move your data, restore from your Time Machine backup: Restore your Mac from a backup - Apple Support. You should not use Wi-Fi or any other method as they often fail.
If you do not have a Time Machine backup, you should create one on your old Mac so it can be restored to the new Mac. To start, you need an external hard drive. Here’s an excellent one sold by Apple: LaCie 2TB Mobile Drive External Hard Drive USB-C - Apple. If your older Mac is an iMac (Late 2015) or earlier, or a Mac mini (Late 2014) or earlier, you will also need this cable. You can then follow the steps in this Apple Support article to setup your Time Machine backup: Back up your Mac with Time Machine - Apple Support.
Once your new Mac is setup with your data migrated, you should setup Time Machine again to keep continuous backups of your data: Back up your Mac with Time Machine - Apple Support.
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