These actions can be done over multiple matches, you just need to do one of each action at some point in your Last Stand career for this achievement to unlock. Objective: To get credit for capturing an objective, you must be inside the zone when your team captures it. You should always get credit for your starting zone unless you race ahead to B, so this will come along with your 50 wins (realistically well before then, unless you somehow win 50 straight matches).

Fortifications: Also in your starting area will be the two types of fortifications you need to activate (the Turret and Pulse Beacon), both of which will cost 250 SHD to activate. You should have enough right in the beginning to grab one.

Perks: The two Perks will spawn in the same locations on the map, so after your first time playing you should be able to anticipate where to go at the 13:00 mark when they activate for claiming. These cost 2000 SHD each, so spend the beginning of the match killing NPCs to fund the upgrade. They also only last four minutes, so you'll have extra chances grab them later in each match.