Not everyone wants to read a whole guide to get one question answered. So here are the short versions, with a link to the long one.
Campaign missions, ARES jobs and missions, operations, dynamic events in the open world, thumping, bounties, Jetball and Team Deathmatch in PvP, or simply exploring New Eden.
The Shared Intelligence Network. Your battleframe is connected to it, and it puts allies, enemies, waypoints and everything else you see on the HUD and the map in front of you.
Play the campaign missions. Since update 1.6 they follow one faction of the Chosen, Razor Wind, and tell most of the story. The Codex entries you find in the open world add the details.
Level 45, per battleframe. Everything you earn after that goes into Elite Ranks. Read more
Because it waits for you to pick an advanced battleframe. Do the mission that sends you to the Advanced Battlelab at Trans-Hub Command. Read more
As a rare reward from Elite Ranks, from rank 10 on, or for Red Beans. Another character with a different starting frame works as well. Read more
The levels beyond the level cap. Every rank lets you pick one of six upgrades for that battleframe. Read more
Because you've locked them in. They unlock after 24 hours, with the next perk point or with a respec. Read more
You can't. Crafting was disabled with update 1.6 and never came back. Gear drops, gets bought or comes out of caches, and gets improved by tinkering. Read more
Find a better one, put modules into its slots, and take it to a Tinker for up to nine upgrades. Read more
They raise one or two stats of the weapon or ability they're slotted in. Three of the same color and rank can be combined into one of the next rank. Read more
Because rarity counts as levels: green is worth five levels, blue ten and purple fifteen. Read more
Salvage the weapons, abilities and battleframe gear you don't need. Read more
Sell things on the market, or turn Crystite into Credits at the currency exchange, up to 1'000 Credits a day. Read more
Buy them with real money, or buy them from other players with Credits through the Red Bean exchange on the market. Read more
Rent one for Red Beans, for a day or for seven. The permanent bikes are sold in the Red Bean store, some of them only during special events.
Collect 50 of them and activate the stack, that makes one Security Key for a Secure Locker. Read more
No, thumpers only extract Crystite in this version. Read more
Small tasks that pay Crystite, XP and bounty points for things you're doing anyways. Press H and select Bounties. Read more
The one that sounds like fun. You can't really pick wrong, since every other frame can still be unlocked later. Read more