Next? Go get some advice from your local independent advice agency such as Citizens Advice or a local authority welfare rights service and secure yourself a representative. Statistically it's your best chance of success but in the first instance get someone to check out what you have so far. Consider very carefully if you want to add medical or other evidence. Check out the Benefits and Work web site for some good resources (I don't work for them).Lots more to be said but that would be my starting point. To answer your specific questions:1) HMCTS will most likely next contact you with a date and time as all the stuff around your availability and reasonable adjustments should have been put on your SSCS1 appeal form. 2) You send any written submission asap, assuming you have asked for an oral hearing. You have asked for an oral hearing haven't you?
No, you just send in whatever extra you have. You will need to keep the bundle for the hearing.
Your submission and additional evidence will be returned to you with numbered pages so you can add it to your bundle in the correct place.