I've been in your shoes before (heavies crew chief) and retrained into a dope cyber gig. Everything you need is on mypers, can be answered by the Career Assistance office, and I even used reddit to get some quick answers. There is a tab for retraining (on the left I believe) specifically for retraining. It has pdfs with the retraining INS/OUTS that show you what careers are undermanned and you can also see which careers offer SRBs and SDAP.

Also if you're a first term airman, that will increase your chances of getting accepted into retraining significantly. Don't hit that reenlist button yet if you can help it. If you have other questions feel free to hit me up on this thread or shoot me a message.