For a new player there's a problem of no matter what weapons you will equip, damage against tougher enemies would be quite pathetic, or your distributor will be draining in a blink.
For unengineered Krait MKII I recommend 3 Large Multicannons and 2 Medium Beam Lasers, all Gimballed. With lasers you will be stripping Shield from NPCs, and with MCs ripping up their hulls. If you see that your distributor is drained too much with Beams, switch them for Burst Lasers, that's as low as you can get, because downgrading to Pulses will make your shield stripping tad slower, not worth to trade for sustain fire IMO. But make no mistake, Pulses are very good weapons, but they are more like universal main firepower rather than specialized as beams or MCs are.
Equipping Class 5 Fighter Hangar and buying Taipan Gelid F might be a good idea. Hire lowest rank pilot and try not to get yourself killed. The problem is with Fighters that until Master/Dangerous they aren't even good as a bait, thus paying for Expert isn't really worth it IMO. You'll have to be patient while levelling, but once he hits Dangerous or Elite, they get pretty deadly and tough.
You can use same loadout for Python, with advantage that, in my experience, it has better heat profile than Krait, thus it will be boiling up from Beam a lot less, while distributor is the same. You'll have to keep at least 3 PIPs for Beam fire. Learning to control power ditribution is vital, especially without engineering.
If you get your hands on G5 engineering, there's pretty much only good choice for Krait MKII (IMO) - again, 3 Large Multicannons, all Overcharged, 1 with Corrosive effect, other 2 Incendiary. And 2 Railguns with Long Range and Feedback Cascade. I can't stress enough how powerful this combo is, it destroys absolutely everything PvE can throw at you very quickly, and disable enemy ability to regen shields from Cells, which is almost like cheating. As a bonus, makes Rails quite cold. You can even take this ship in PvP and feel confident.
For engineered Python, I use 3 Large Beams, all Efficient, 2 Oversized, 1 with Thermal Vent. Your heat will never go over 50% as long as you stay on target. And 2 Seeker Missile Launchers with High Capacity and Oversized upgrades. It's strictly multi-purpose PvE build. Once you strip shields with Beams (while your G5 Distributor will barely notice any drain), target either Drives, Weapons or Power Plant modules, depending on target, and you'll make quick work of anything. It's rather fun build, but still quite effective. Of course nothing stops you to equip it same way as Krait II for max efficiency in combat.
Fire groups are very simple, Large weapons on first Fire Group, Medium weapon on second one, in any order you find fancy.
"Friendship Drive Charging" COVAS