You will probably need at least 5 people to erect a
tripod made with steel poles:
At least one strong person to
lift each of the two main legs by walking down beneath it from apex to base; one person to do the same with the third
leg and at a crucial moment, to swing this leg out and to prop up the 'A'; and one person with their foot braced
against the base of each main pole to stop it skidding forward.
With aluminium poles the job is easier, demanding only 3 people.