You also need to
mention if you can't do anything 'reliably,' i.e. if it's not safe to
do so; causes you pain during/after an activity; if it exhausts you afterwards, or you're very slow
at achieving an activity (such that it takes you more than twice as
long as someone without your problems would face).
The following link is lengthy, but shows the 'descriptors', how & why points are awarded, etc: https://www.gov.uk/government/publications/personal-independence-payment-assessment-guide-for-assessment-providers/pip-assessment-guide-part-2-the-assessment-criteria