The First-Tier Tax Tribunal judgements are very difficult to appeal and you cannot appeal simply because you disagree with them. The Judge will have to have made an error regarding the law, not simply that the facts were misunderstood, although there is one exception we can discuss with you if you are in this position.
In order to be allowed to appeal, you have to complete a form and ask the Judge that found against you for permission to appeal. If that is rejected, you can then ask the Upper Tribunal for permission to appeal. If that also fails, you can ask the Upper Tribunal for an oral hearing to put your points forward. If that fails, there is no other route to appeal.
If any one of those applications for permission to appeal succeed, the matter then moves to an appeal hearing in front of an Upper Tribunal Judge and this will be at the High Court.
In terms of timescale, you have 56 days to appeal a First-Tier Tax Tribunal decision. If you ask for permission to appeal, this normally takes 2 weeks to get a result and then you have 28 days if you want to ask the Upper Tribunal for permission. Again, that can take 2 weeks to get a decision and you then have another 28 days to seek an oral hearing. It will then take less than 2 months to get a hearing and, again, there is no route forward if you fail to get permission. Therefore, from the moment you receive a negative decision from the First-Tier Tax Tribunal, the process can last a further 6 months if no permission is granted and 2 years if you do get permission to appeal.