Disvaana maggaa okkamma aññatarasmi.m
rukkhamuule paññatte aasane nisiidi.

disvaana - having seen, past adverbial participle from 'passati'
(see the note about 'gerunds' below)
maggaa - from road (ablative from 'magga')
okkamma - approaching (present participle from 'okkamati')
someone approaching
aññatarasmi.m - at a certain (locative)
rukkhamuule - at the foot of a tree (locative from 'rukkhamuula'
< 'rukkha' tree + 'mula' root)
paññatte - on the pointed out, appointed (i.e. special) (locative
according to the case of aasane)
aasane - on the seat (locative)
nisiidi - (he) sat down



Note about 'Gerunds'

In my humble opinion 'Gerunds' was the closest term that
English-speaking grammarians could find for Pali adverbial participles.
Furthermore, these adverbial participles have obvious equivalents in
Russian

Russian Pali English

davaya daaya (while) giving

dav datvaa having given

uznavaya abhiññaaya (while) learning

uznav jaanitvaa having learned

Such indiscriminate categorization under 'Gerunds' does not allow to
distinguish times of adverbial participles and their shades of meaning.
Understanding these forms as adverbial participles gives a chance to
learn the subtle nuances of their meaning.