Brave Trial has recently been reworked and no longer has a store. It now has two Modes, Day Mode (the existing brave Trial stages) and Night Mode (the new stages). Night Mode added another 15 stages(levels) and starts drawing its heroes from the Arena Top 500 team Histories. The 
Dragon Scales gains on each level has increased for both Day and Night Modes with check points at stage 3,6,9,12 that give bonus Dragon Scales and 
Gold .
Below is a guide for early game players to be able to complete the first 15 stages of Brave Trial (Day Mode).
Brave Trial[]
Before you even tap on the Brave trail icon go into your heroes list and UNEQUIP ALL your heroes. Once this is done you can then enter Brave Trial.
If the teams you are up against are 4 star and below with only 1 5 star in them you can most likely beat those teams with a Fully maxed 5 star 
norma with 4* star gear, and at least 2 other heroes as support. If you are on a new server and just starting a fully maxed 5 star Norma should be the only hero you will need to pass Day Mode.
After stage 6 Day Mode you have the option of healing or restoring a hero using Trial Badges in the Altar of Trials. For the first restore you need 3 Trail Badges then the cost goes up by 1, for 1 heal it costs 2x trial badges and you get 2 heals at 2 trial Badges before the price will go up by one. After each match win or lose this is reset back to 3 trial badges for a restore and 2 Trial badges for a Heal. So try to only restore your best hero and leave the next to restore on the next turn if you need to. Same with the healing heal only 2 heroes each turn.
If you are still having trouble you can pop out to your hero list and equip an artifact and top gear to Norma to finish. Once you gain a pet monster an unequip Norma with your pet should be all you need to start. So maxing your Norma and Pet (once you get them) should be your priority over leveling any 4 star or lower heroes. Note: You get a free copy of 5 star Norma by registering an account (which is free to do).
norma at 6 stars and teamed with your pet & with a bit of rnd luck you should only need to use norma as a solo run, you will only need to add heroes to your team when you face a mirror team (the brave Trial team you used in the previous level as your opponent). By the time you get norma norma to 9 stars your pet should be at, at least tier 3 or close to tier 4 on a new server this combo might even let you get half way through Night mode.
Another hero you can use in a similar way to norma is a maxed out 
vesa. Using a 5 star vesa and norma together can also help you clear Day Mode.
As you build up your heroes Brave Trial will start to get a little bit harder to clear Day mode one thing that will help is if you limit the number of heros you have at level 40 or higher another thing that will help is maxing out your pet monster as your monsters power does not count towards you overall hero power.
Solo run Heroes[]
These heroes can most likely be able to go through Day Mode with little to no team support just the use of your Monster.
norma,
Vesa, valkyrie valkyrie (will need to use healing to recover or maybe even a healer for some stages).
norma norma Note: the opponents you will be going up against in Day mode are the arena defense team history for the servers in your trial. Each trial pulls from its pool of at least 10 servers eg s301 to s310 are one trial.
Night Mode[]
This relies a bit more on random luck when you hit stages 3,6,9,12 & 15 you will be going up against Arena Crystal Crown League Top 500, 300, 200, 150 and 100 players respectively.
Tips[]
Opt 2. After you have unequip all your heroes and entered Brave Trial and opened the first stage a few people will exit brave trial equip your solo run hero with 6 star gear and artifact or just an artifact then re-enter brave trial.
2. Proven to work against a single E5 Aida opponent is 5 star team of 2 Oberon, 2 Amen-ra, 2 Oberon.