This mission is very easy, being the first Terran Mission. Your main worry is losing your SCV's, something you must not do.
Starting out, you should split your Marines and SCV's into separate groups, then move toward your base at the bottom of the map with your Marines. After meeting Marshall James Raynor, you will meet a bit of resistance on your way to your base.After you clear the area of hostile beings, move your SCV's down and begin gathering resources. Don't bother making any more SCV's: it's a waste of time and minerals. As soon as you have 150 minerals, grab an SCV and tell it to build a Barracks. When the Barracks is done, just build Marines until you beat the mission. That's all there is.
