recover external 1tb seagate hard drive data when installing time machine and did erase

HI,

i have bought new Macbook pro for Graphic Designing.

i have use my external hard drive 1 TB seagate for back up

but when i plug in with macbook pro the message was came for time machine backup

when i say yes it was asked me for erase and i did that but after that i check nothing in my external hard drive.

could you please give me solution how to bring back my external hard drive back up.

i am so worry, please help me in this matter.

Thanks and your support