cant really teach you much, i do learn as I am doing it, but in general you need to know the particles direction and changed them 1 by 1 from the workshop, terrorblade uses some of its original model particles so by changing the color of the arcana it did change the original particles as well, i did a test run and it came out ok'ish , tell me which color do you want and i will do my best https://dota2.gamepedia.com/Prismatic_Gem here how it looks with
what do you mean if u can do the arcana u can change the default as well , the particles are placed in particles/units/heroes/hero_terrorblade. do you want me to send you the vpcf files so you can see how i did them? hopefully that will help
did you follow this guide ? https://dota2shadymod.forumcommunity.net/?t=59639735 i started from there but rather than adding Remap control point to vector and change the values , i uncheck "Remap control point to vector" on all particles and change the "random color" value, this works only on particles that you can use prismatic gems, Here is a list of items that have prismatic gems and bellow that you can get the color values https://dota2.gamepedia.com/Prismatic_Gem HF