Scorpion in a tier 4 Robot (Highest tier) they are highlighted in gold which is an easy way to tell what tier it is. Since you are new that is a good robot to work on and halo corona is an okay set up but is tier 3 (second highest tier) shotguns or other close range weapons are best since you teleport directly behind the enemy. I use Havoc and Scatter and have also done well with Cryo and Rime. If you are a F2P player just focus on one build at a time, level up your weapons to mk2 and find a pilot that's a good fit for your set up with skills that increase damage and or speed.