Paint the metal, wood, flesh as normal.
Tights and undershirts in a mix of pale browns/tans/greens/buffs.
The overshirts are the "livery" -- the uniforms of the day. Generally these would be split vertically -- left-hand-side in one primary colour, right in an another. It could also be a single colour, split into quarters (done in two colours) or horizontal stripes (but this was rarer).
Popular colour schemes were red/blue, white/some-other-colour, all-red, all-blue. They sort of seem to follow heraldic rules about how to make fields (metal and non-metal), but the rules are broken more often.
If you're doing generic medievals, paint them in batches sharing the colours, then mix them up into your units. They would be issued livery by the man who hired them, but in battle they'd be mixed up and grouped by weapon (all the archers in batches, all the polearms in batches).
If you're after doing HYW, the livery should include more white with a big red cross on it; the king required all the English soldiers to wear it.
The quilted/striped tops are padded armour. It's basically like a duvet – linen stuffed with shreds/feathers/wool/whatever. I tend to do these starting light brown and shade up to buff/linen tones.
Here's some of my 28s from that era;
receives a gift from his wife…
