How do you volunteer to join Ukraine's defense forces? How can veterans help?

I caution against this for those of us who still have a pathway back into US military service.

1) You're over all contribution to the fight against Russia will be most utilized where you are now.
2) I really think US service members wont have long to wait. So do you want to go in as a SSG or some dude with a US passport that is only there to pull a trigger.
3) You will be on your own, dependent on the whims of the Ukrainians and lord forbid the Russians if they get their hands on you as a non US military soldier. They will write their own rules.
4) How you get back home is entirely unknown. It could very well be, OK thanks, we don't need you anymore. You have boots and a passport, so start walking west.

SSG Carlos Madden All good questions but I do have a comment on one item. If you are dedicated enough to want to volunteer to help Ukraine, I wouldn't expect to get paid.

SSG Carlos Madden Military Times spells it out pretty good.

https://www.militarytimes.com/flashpoints/ukraine/2022/02/27/want-to-go-fight-for-ukraine-heres-what-to-do/

I read something a few days ago, but can't remember where. The basics were to contact the Ukrainian embassy; fill out an application and then be interviewed for them to decide if they want you to go help. That would also be my guess as where to get most questions answered as well.

U.S. law does permit any U.S.citizen to volunteer as long as you are NOT volunteering to help fight against the United States, if you decide to use caution because that doesn’t mean a prosecutor somewhere won’t get a burr under their saddle and try to find some sort of crime to charge you with upon return to the states, service members are not authorized to volunteer it is against the law unless you get something to help cut through all the red tape but I can be done. If you do this make sure you have all the information available to protect your legal rights as a citizen.
Good luck to all of you my brothers and sisters and stay safe and keep your heads down and make every shot count and remember 1shot 1 kill follow the rules of war and the ROEs and the Geneva convention

Someone else shared the link to the Military Times article. US citizens can indeed generally serve in foreign militaries.
Based on the information in that article, it appears they do vet applicants and that you should bring at least some of your gear. "On a volunteer basis" sounds like you may not get paid.
I read something where someone told how he arrived at his unit while they were in contact and upon finding out that he was the new guy he was directed to where to obtain a weapon.

Sorry Staff. I can't answer that. I know people who went to fight with the Peshmerga against ISIS. They were provided weapons, and minimal equipment, but told me it's better to outfit yourself.

The best way is to enable the EU and the US to help Ukraine. Letting Russia take over Ukraine? You are enabling the communist to gain more power and expanding the communist's global influence. You don't care about China taking over Taiwan? Sounds like you are a communist supporter. Only a certain group of people always denounce communism and yet support the communists taking over the world.

Either way, I would be willing to go fight as a civilian combat veteran, or if there is a possibility of being recalled. If I were to be able to go over on my own, Id appreciate a ride, but I would find my own way there and back if need be. Hell, I might just make a new home in the Ukraine.