just received the dreaded PIP claim pack

I am in a state, I was on lifetime DLA, now been asked to claim PIP. I am unable to see my GP until the 25th April and also the most recent time I saw a mental health nurse was March 2017. I recently bought the PIP guides but apart from some GP appointments I can submit my own evidence but I am at a loss as to how to go about filling in the forms in terms of what evidence I should supply

My first call to the DWP was yesterday and they said I would get the forms to fill in in about a 7-10 days.

I was on higher rate care and low rate mobility.