OSDev.org

I do everything in Bare Bones OSDevelopment but It wont work!

The Grub said that

erro:there is not multiboot
but when I fixed it
not it says error:boot the kernel first!!

While I am just trying to guess from your vague description, I think your multiboot header is missing. Give it a check, it should be in boot.s (assuming this is the Bare bones tutorial and not for the other languages). Also it must be at the first part, if it is in any other part of boot.s or have exceeded the first few bytes then it won't work. If that is not the issue I don't know, your question seems really vague and someone else should suggest how you can be more descriptive if you want help. Also, how did you fix it? Added code? Removed something? Also ensure you are using a cross compiler, sometimes problems can arise from using the normal compilers.

but when I fixed it

?
How did you fix it?

not it says error:boot the kernel first!!

I'm not clear of what your problem is. Did you load the kernel or just typed in boot? Also, the tutorial clearly has a GRUB Menu file, which you should be using.
IIRC you must: (GRUB Legacy, assuming your boot device is your root device and kernel's filename is "kernel.bin" and it resides in the root directory)
"kernel /kernel.bin"
You may get some information from GRUB here.
"boot"
And GRUB should load and boot your kernel.

I suggest you start paying a bit more attention to the forum rules - especially the parts on required knowledge and smart questions.

Meanwhile I'm going to do everyone a favour by locking this thread as your "error messages" are technically fake, your descriptions are unhelpful and your thread title is in clear violation of the abovementioned rules, meaning that you won't be able to get proper help without countless unnecessary queries. It is your problem and therefore it should be your task to maximise your chances at getting help. Therefore it's better right now to read everything through properly and then try again with a properly formulated query.