My Mac has no operating system and it won’t start up in recovery mode what are my steps to fix this computer?

The "A1236" designation shows up as an iPod Nano. Even if you had not mis-typed the designation, it would be to generic to help in regards to knowing OS compatibility. The serial number should be located on the bottom of the laptop...you may need to use a magnifier and a good light. Older non-unibody laptops will have their serial numbers located in the battery bay with laptops with removable batteries.

Without knowing the exact model, we cannot tell you which versions of macOS are compatible, nor can we provide instructions or other options.

If this laptop can utilize the online Apple Diagnostics and has access to Internet Recovery Mode, then it means that it is a Late-2009 to 2012 model since 2012 was the last year the Macs had white/gray screens during boot.

Do you have access to any other Macs? If so what exact model(s)?

Is this a 13", 15", or 17" model?

I think this laptop has more issues than just no OS. It may be why there is no OS on it.

It really helps to know the exact model of your Mac and the previous version of macOS you were using before erasing the system. You can get the exact model by entering the system serial number here:

Check Your Service and Support Coverage - Apple Support

How did you create the USB installer? What happens when you attempt to boot from USB?

What happens when you attempt to boot into Recovery Mode and Internet Recovery Mode?

Why did you decide to erase & reinstall macOS? That problem may also be why you are unable to access Recovery Mode or boot from USB.

It would be just your luck that the previous owner wiped all traces of macOS from the drive by installing Linux or Windows on it, so the drive (if there is a drive in it) would not be recognized by any form of macOS looking for an internal drive.

That early 2011 MBP shipped with OS X 10.6.6 on it and can only be upgraded to macOS 10.13.6 (which is also long since unsupported by Apple). You probably cannot get it to boot from an OS X 10.6.3 DVD, it did not support booting into Recovery, and until you resolve the internal drive format, you may have a paperweight.