PlanetCraft and Planet of Cubes Forum

I'm no admin, but if the enchantment table is anything like MineCraft's (which it very likely is), the more bookshelves you have around your crafting table, the higher your enchantment table's level will be, thus you get better enchantments from it. To enchant items, you'll need the item you want to enchant and 1-3 lapis, one lapis is for the cheepest enchantment (the most upper available enchantment), two lapis is for the medium level enchantment, and three lapis is for the most expensive enchantments (the lowest available enchantment). The more expensive of enchantments you go, the more likely that it'll add a multiple enchantments to the same item.

Redstone repeaters are also very likely to be the same as their MineCraft counterparts, though as I'm not a big redstone person myself, I don't personally know how they work, but there's countless MineCraft redstone tutorials on YouTube.

On PoC, there's no way of making your sword unbreakable.

You may be confusing it with the unbreaking enchantment, which instead extends the durability of a particular tool or armor, the higher level of unbreaking you have the less likely an action performed with the enchanted tool or armor (mining, attacking, taking damage) will take a durability point off of your item, however like all other tools in PoC, your item will still break eventually, but unbreaking's still pretty useful in many situations.

As for the "flammable" enchantment, you're likely either referring to the fire aspect and flame enchantments. Fire aspect is an enchantment that allows a particular tool to set fire to an animal, monster, or player when you attack it, this can be useful when trying to get cooked meat from animals, or wanting to cause extra damage to mobs especially when combining fire aspect with sharpness. Flame is an enchantment that's fire aspect for projectile weapons such as bows, and crossbows, in which instead of punching a mob with the tool to set them on fire, you'll need to shoot arrows to set the mob on fire. In MineCraft, flame enchanted bows can also set off TNT, though I currently can't confirm if Solverlabs added that yet, but you could still test it out if you'd like.

Hopefully this helps you out.

Also, in the future, if you're needing help with the game, putting the question onto the Help and FAQ section of the forums, and having a descriptive title; (for example in this case, the title could be "help with understanding enchantments and redstone repeaters") will make it more likely that Pocadimin may respond to your issue.