So I just learned DR for FMC, but I was having trouble setting up the number of corners and edges needed to be solved to set up to a DR trigger.
A lot of the time I end up getting 6 or so corners unsolved and can't find a way to get fewer unsolved without messing up edges or having a really bad solution.
Also, what should I do after I finish DR?
(The DR triggers I know are only 4C4E, 3C2E, and 4C2E.)
This was the trickiest part for me, but I was able to understand it eventually. It is kind of hard to explain with just words and no video or examples, but I'll try my best.
Basically, after EO, you have an X amount of corners and an X amount of edges left on the cube that are not in DR. You first do something called RZP, where you reduce something like 6c4e to something like 3c2e, or any other triggers you know. RZP should only take 1-3 moves, and if it is worse, than you should skip the EO and use another EO in the scramble. For DR, it is very important that you find many EO's, and if you are having a hard time finding EO's, you can NISS or use other axises, or watch example solves.
For RZP, you setup U and D moves to an R or L move to make the reduce to a trigger. For example, if I had 6c4e, and I wanted to get 3c2e, then you can see that I need to reduce it by 3 corners and 2 edges. That means that I want to do U and D moves to get certain unsolved pieces in the Right or Left layer, then you do an R or L move which will move a certain amount of edges and corners from being unsolved to solved. After that, you move the unsolved pieces around to setup to a trigger, and then you do the trigger.
After you finish DR, HTR is very important, but it is way more harder to learn than DR (Took me months to fully understand how to do it in a short amount of moves).
Those 3 triggers you know are enough to be good, and learning more might help, but it will only help you a little bit.
I would also recommend getting help from people on the FMC thread, because they know more than me. This video might help you visualize it better:
