Shamusy
Welcome to the forum, you might want to have a look at the following FAQ which explains where everything is
Welcome to Benefits and Work The ESA Appeal guide has links to the SSCS1 form that you will need to complete and the Submissions guide has a complete example that you can use to help you fill it in, you do not need to provide detailed reasons at this stage for your request.
www.benefitsandwork.co.uk/help-for-claimants/esa1 Once your appeal is accepted the DWP will prepare their submission to the hearing and send you a copy, whilst you should wait until you receive this to finish and submit your own, you should start to prepare your own case, an increased award will only be made by your showing that you score the extra points for one, so I would start by going back through your ESA50, the assessment report and the ESA Claim guides to see how you might show this is the case.
If you have further questions then please reply to this post and we will do our best to help.
Gordon