Roman languages tend to express with a verbal periphrase what in English is expressed with an adverb or an adverbial adjunct. To this categorie belongs as well the construction stare + per + infinitivo and in this case there is a verbal periphrase as well in English.
Sto per uscire.
I am about to go.
Ci stiamo per trasferire a Londra per lavoro e cerchiamo un appartamento.
We are about to move for professional reasons to London and are looking for a flat.