First of all, welcome Richard, to the hobby, the game and the forums! And as a Dawnish player myself, to the nation!
Do you have any idea which event(s) you’ll be able to make?
Chain and bright colours is fine, I suspect you’ve looked at the style guide for Dawn? There are a few groups in red in Dawn, so you might get mistaken depending on symbols or other colours 
The basic Dawn kit, usually worn by Knights Errant, is the yellow sun on royal blue. That’s the national symbol, recognised by everyone as “generically Dawn”. Most Houses have their own symbols, many nobles have their own specific symbols, and so there are a lot of different ones.
As a quick guide:
Yeofolk generally wear nothing special, or the colours of their House.
Knights Errant (wannabe-nobles) wear the Sun-on-Blue and/or the colours of the House they’re aiming for.
Nobles wear the House colours, House symbol, and any symbols specific to them.
Examples:
Bob is a yeofolk of House De Rondell (symbol is silver griffon and 3 silver crescent moons on light blue), and wears neutral colours with a blue and silver sash, and a blue hat.
Sir Bobbie is a Knight Errant testing into De Rondell, and wears a tabard of Sun-on-Blue over her armour, or a light jacket in De Rondell colours when in camp.
Lord Robert de Rondell wears the colours and symbol of his House, with the griffon sometimes replaced by a dragons head, in memory of the drake he killed in single combat.
You can start a character at any point on the social ladder, but the fancier the kit, the better for the higher you go. That said, there’s some very flashy yeofolk and some rather battle-worn nobles, so don’t worry too much.
The classic advice to new players is to start as a Knight Errant; a wandering knight looking to win nobility as a member of a Noble House. As this gives you the perfect in-game reason to be wandering around asking questions and chatting to everyone and trying to find some folks you like.
(I can reccomend finding a group of folk to hang out with as a starting point, whatever you do. Have you found the Dawn Facebook group yet?)
Backstory ideas…
The big things in recent history have been the attacks of the Cold Sun, and the conquest of the Barrens.
The Cold Sun forces attacked from another dimension (effectively) and did quite a lot of damage before being driven off by Imperial forces. They didn’t hit Dawn as hard as other nations, but I suspect several Houses and groups were over-run, leaving scattered survivors (that’s you) who might come to Anvil to rebuild their fortunes.
A year or two ago, the nation of Dawn completed a mighty quest, conquering the rich territory of Barrens from our old foes, the Druj barbarians. Knights and ambitious young Houses flooded in to build new legends on the blood-soaked hills and valleys. Maybe you could be one of them?
Or perhaps some scion of an older House in Dawnish lands, recently finished a stint in the armies, or intent on striking out by themselves?
I am happy to answer questions, talk through backstories, and discuss kit or character builds!
Have a deeper look at Dawn on the wiki, and see what you think.