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There is a software from Apple called Windows Migration Assistant which you can install on your Dell laptop and it will allow you transfer files from your PC to your Mac.
Download and install it on your PC from here --> https://support.apple.com/kb/DL1557?locale=en_US
Refer the instructions in here --> https://support.apple.com/en-us/HT204087
If you already setup the Mac, then go to Applications > Utilities folder and open Migration Assistant. Then follow onscreen instructions.
If you have any questions or would like any additional information, please don't hesitate to ask
Remember, both computers must be connected to same network.
Or you can connect them directly using an Ethernet cable. You have to buy Crossover Ethernet cable from a computer store to connect both. Then you can transfer information between them using Migration Assistant application.