ok, I'll answer your many questions for you...
1. you are only a low level at the moment so a lot of power players will ignore you as an ally (allies are used to augment your party on quests so the higher the * of the ally leader the better generally)
2. you are allowed to send a maximum of 200 braves to people in 24 hours. each time you send them brave you earn brave in return. at low level spam everyone with brave. you cash in brave pionts for cards in the "card pack" section. more brave, more cards. btw you will mostly only get 1* or 2* cards this way, extremely rare is 3*
3. Ally points are earned by assisting your allies if they use your leader for a quest. you use ally points in the "skill" section (might want to boost the amount of brave you earn here to begin with)
4. battling is done with 5 of your cards plus 5 allies. if you win, you steal luna and if you chose to battle for an artifact you get that as well. completing an artifact set awards you a monster card to use to defend against others who battle you. once a set is complete the artifacts that make up the set can't be lost, but they can be lost (and you have to re-aquire them) until the set is complete
6. monster cards are what you defend with when someone attacks you in battle. no monster cards = easy pickings, but veteran players will most likely leave you alone to begin with as your luna reserves are going to be too low to bother raiding (no longer applies if your luna reserve goes over 100,000)
7. when you lose a quest you get less xp and luna, that's it. you can re-attempt the quest after the cooldown period has expired. no other penalties apply.
8. when your level increases as opposed to card levels, it doesn't affect much BUT you are unable to trade, buy or sell units or items to other players until you are level 31.
9. the yellow tiles mean a more powerful unit is available to find. from 3-5 onward, they are 2* cards
10. eat the 1*'s. you are too low level to get a 4* until you earn one in an event or finish the login bingo so you might as well boost your existing cards. Also, remember that you are unable to sell untill you are level 31, so you have a while to go. Later you can look at selling boosted card sets (or feeders) for other items or luna.
11 yes there was no 11th question asked but this is an important answer anyway. You are awarded some Time Elixirs (TE) and Potions (Pots) when you start. If they are marked with a (p) it is ok to use them in quests or training but if they are not, then they are TRADEABLE - try to hold on to them and you can use them to buy 4* and higher units once you have reached level 31. btw, te(p) and pots(p) are used first in preference by the game when expended.
This should help, but you should also read the Game discussion stickies