If you held the reset button for 7-8 seconds while the Time Capsule was powered on, then you performed a Hard Reset......which erased all of the network settings on the Time Capsule and returned them to factory default settings. The good news is that a Hard Reset does not have any effect on the data stored on the Time Capsule hard drive.
A USB connection from the Time Capsule to your Mac will not work, so do not attempt this. The USB port on the Time Capsule is there only to add an additional hard drive for additional storage.
So, you will need to try to set up the Time Capsule again, just like you did when you set it up originally. You can use the same device name, wireless network name, passwords, etc that you used before if you wish, or set up the Time Capsule with new names and passwords.
Once that has been completed, you will need to set up Time Machine again to back up your Mac to the Time Caspule as follows:
Click the Time Machine "clock" icon at the top of the Mac's screen
Click on Open Time Machine Preferences
Click on Select Disk, or it might say Add or Remove Disk
Select the current backup disk to highlight it, then click Remove Disk
Restart your Mac
Open Time Machine Preferences
Click on Select Disk
Select your Time Capsule disk, which is likely named "Data"
Click Use Disk or Use for Backups
Time Machine should start a new backup again within a few minutes