im new to starters orders and im looking for advice on spotting good horses in jumps mode

It depends what you mean by good horses. There are good 'in game' horses & there are good race builder (league) horses.

Depends, if you use artmoney to give yourself loads of money, then you can buy anything you fancy, however if you want to play the game properly, then look for horses coming out of sellers and claimers, with only a couple of runs under their belt, or horses that have been running over unsuitable distances. Good place to start

Sorry I'm new to this game. What's the difference between "in game" and race builder (league) horses?

"Race Builder" is the tool you use to take your best game horses, and use them to take part in the online racing league. Basically you need some pretty amazing horses using bloodlines that you have built up over many seasons, before you even think of joining the online league!

Many thanks for that .I only got the game a couple of days ago so i'm still finding my feet

While it is fair that in general terms you need superstars simply to compete at the top level of SOPL (the online league), a lot of effort has gone into providing opportunities for trainers/horses at all levels. So don't be put off joining the league but do be prepared to have a bit of a reality check - which pretty much all the leading trainers have experienced at one stage or another.