For my horses condition I see 2 bars right next to each other, a red and a green one. Is my green where my max stamina is and the red is what it is at now? And if the red is a lot lower than the green does that mean I should give the horse a rest? Also, when do you guys put your horses on blue, like after the race for a few days?

The green bar is his fitness level, so a horse not in training will have a low bar, when you set them to full training this will increase and you will want it full before they are racing. The red is their available stamina, sort of, or their energy, so as you train them on full green rises and the red will reduce, when not training the reverse will be true so the bars are basically antagonistic of each other. When you deplete the red bar, you cannot increase the green (this will be when you see messages such as 'has had about enough racing this season') So you need to manage both to a degree.

I tend to find on manual training, blue when not running (or jumping, agility etc if the horse needs it) amber if they have a lot of racing in a short period and you do not want to let them fall too unfit (the 2yo season for example is quite compressed as is the early part of their 3rd year least on a UK schedule) and red when they are due to race. Typicallly on red training, it takes about 20 days give or take to move a horse from red condition to green condition, race fit.

Some horses will only really give you 4/5 races per year, others 8-10.

Josh