There is a BLUP schedule linked in this forum and you could try checking out this one as well.

I couldn't find any on the blue schedule that matched the Belgian riding pony unless I'm still not actually understanding the blup schedules

You would find the schedule in there that shares the same top three skills of a Belgain Riding Pony
Their top three are Stamina, Gallop, Jumping

The above linked forum has a schedule that mentions it works for Belgain Riding Ponies

Steps marked (Optional) are just that. They won't help with the BLUP, but they may help your horse get wins. Optional steps are more recommended for lower skilled/GP horses.

For rookie schedules, there will be a value "X." To find X, use the following:
X=rookie limit - (skill GP x 0.2)
The rookie limit can be found in section 2.5 of the equestrian center manual.
Skill GP being the GP for that specific skill (ie speed, dressage, etc) which can be found in the horse's genetics tab.

Stamina/Gallop/Jump schedule
Works for Trakehners and Belgian Riding Ponies

Classical
Board in Mountain EC
Foal games (optional for BLUP)
Mountain rides until training is available
Train jump (no higher than X {see description} for rookie, fully if not)
(Optional) train dressage (no higher than X {see description} for rookie, fully if not)
Enter (rookie) cross country comps until no gains
Finish Mountain rides
(Optional) train speed (no higher than X {see description} for rookie, fully if not)
Enter (rookie) gallop comps until no gains
Finish training stamina, gallop, and jumping and do Forest rides (switch to forest EC if you can)
If wins still needed, try trot comps
Age to 10

Western
Board in Mountain EC
Foal games (optional for BLUP)
Mountain rides until no gains
Train stamina, and jump (no higher than X {see description} for rookie, fully if not)
(Optional) train trot (no higher than X {see description} for rookie, fully if not)
Enter (rookie) trail comps until no gains
(Optional) train dressage (to just below rookie limit if rookie, fully if not)
Enter (rookie) reining comps until no gains
Finish training stamina, gallop, and jump and do forest rides (switch to forest ec if you can)
If wins still needed, try barrel comps
Age to 10

SWAP Schedule [Recommended IF you have the VIP perk to change specialty at any age]
Board in Mountain EC
Foal games (optional for BLUP)
Mountain rides until training is available
Train jump (no higher than X {see description} for rookie, fully if not)
(Optional) train dressage (no higher than X {see description} for rookie, fully if not)
Enter (rookie) cross country comps until no gains
Switch to western specialty
Finish Mountain rides
Train Stamina (to just below rookie limit if rookie, fully if not)
Enter (rookie) reining comps until no gains
Finish training stamina, gallop, and jump and do forest rides (switch to forest ec if you can)
If wins still needed, try barrel comps
Age to 10

BRP Schedule:

Belgian Riding Pony Blup Schedule
• Horses should already be boarded in forest EC with shower and trough
• Foal games are optional
• Complete forest rides
• Train stamina, gallop, and jumping
• Get wins in barrel racing
- Ask for fillers in team-fills - be sure to mention horse name, comp type, and % difficulty
• Cancel boarding and board in mountain EC
• Complete mountain rides
• Enter 25 trail class for gains (and make sure you've gotten all gains from barrel as well)
• Age to 10

a trick is while you are training stamina, gallop and jump, i enter 2 reining comps to get stamina and gallop bolded for competitions and it helps when a better horse comes through, because lets face it we get stomped all the time but it does help