Before you walk or run up to (8)
I believe the answer is:
preamble
'run up to' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how one could define the other.
'before you walk' is the wordplay.
I cannot really see how this works, but
'before' could be 'pre' (prefix meaning 'before') and 'pre' is found within the answer.
'walk' could be 'amble' (ambling is a kind of walking) and 'amble' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'or' is the link.
Can you help me to learn more?
(Other definitions for preamble that I've seen before include "Overture" , "Foreword, introduction" , "Introductory explanation" , "Explanatory foreword" , "the first thing one reads?" .)