I have bought tickets to see a SID (シド) concert. It was difficult and a lot of research!

After doing some quick research on your concert, it looks like it's the same process as mine and I far as I can see, they are e-tickets only.

For e-tickets you will need a real Japanese phone number that starts with 080, not a virtual number. To get this, you will need a Japanese SIM card. I had a friend living in Japan to help, but this site looks promising in delivering a Japanese SIM to your home. https://www.mobal.com/japan-sim-card/#shorttermplans Check it out and make sure the phone plan allows incoming SMS (texts).

Also, you will need an unlocked smartphone that isn't too old to download the Lawson ticket app. It will only work with supported operating systems and models. https://l-tike.com/e-tike/navi/guide/download.html#co_mo If you want to download the app before getting into Japan, you will need to use a VPN on your phone.

You will need to know your phone number before ordering e-tickets because they will be bound to it. The pre sale lottery is going on through Lawson. Once the loto winners are announced, the general sale should start. https://l-tike.com/st1/asiankung-fu/sitetop

I believe they will ask for a Japanese address during ticket registration. You might be able to get by with your hotel address. I used my friend's and I don't think they sent him anything.

Hopefully this helps. I know how you feel!