Then start by reading the article on how to use Target Disk Mode. You will boot your old computer into TDM. The two computers will be connected using a Firewire cable. New MBPs do not have Firewire ports, but Apple does sell a Thunderbolt to Firewire adaptor you can use. Hopefully, your old computer has a Firewire port. If it does not then you cannot use TDM.
Once set up your new computer will be able to access the old computer's disk drive. You can then migrate your data from the old computer using Migration Assistant. Do the whole enchilada. You can delete what you don't want after completing the migration.
If you have not yet started up the Setup Assistant on your new computer, the I recommend using the Setup Assistant's migration option. This will transer your old Home folder to the new computer as the initial admin account.
How to use Migration Assistant to transfer files from another Mac