There are two ways of applying for your Provisional Licence.
1) Applying online is probably the quickest and most convenient way. This can be done by visiting GOV.UK.
2) You can also get a D1 form from the post office, fill it out and send it to the DVLA.
Since June 2015 you will no longer require a counterpart for your Licence. To prove your entitlement you will need to go online and generate a code which you can then pass on to your instructor so that they can check to see if you are entitled to drive before your first lesson. You can do this by clicking here.
You will not need to do this for your driving test. The DVSA will already know what your entilement to drive is.