There is a three month waiting period which will begin when you provide evidence of having limited capability for work, this is known as the assessment phase (13 weeks) you are then assessed. Our UC/ESA Claim guide explains the criteria you are being assessed against and how to explain your limitations. See
You may be placed in the limited capability for work and work related activity 'LCWRA' group if your condition is such that you are not thought capable of preparing for work, check out the guide above for details.
If you have more questions then please return to the forum and we will do our best to help.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems