Aim to end the hour with more than $10,000 [S1], Career level 6 or higher, and your New Recruit discount spent. Do not buy a helicopter, a FOB or a hammer yet. All three lose money on a $10,000 [S1] starting balance.
Before your first match, visit the firing range. Everything is unlocked and free there, so learn the controls without paying for mistakes.
Opening kit: binoculars ($75 [S1], or $38 [S1] with the discount), the free faction rifle, one magazine and five bandages, under $1,500 [S1] in total. Join a squad with Escape, then take a helicopter or vehicle to the zone. Never run it: the zone is roughly 3 km from spawn.
In the zone, spot enemies from cover, revive and bandage teammates (never yourself), and press Rebuy when you die. While you are still under Career 9, buy the Field Resuscitator blueprint ($10,000 [S1] full, $5,000 [S1] discounted) first, then Level 1 Armor + Helmet ($17,500 [S1] full, $8,750 [S1] discounted).