Gather basic ingredients:
Lab-grade Dimethyl Fumarate (97% or more)
Empty gastro-resistant (enteric) capsules, size 1
Plastic foil or paper to cover working surface; Surgeon's mask or similar; Thin rubber gloves
Capsule filler, very handy; Elecronic scales
Cover your table with plastic foil/paper or something; Put on gloves to avoid skin irritation; Put on surgeon mask (not mandatory but handy if you sneeze or something, you don't want DMF all over the room).
DMF isn't toxic but irritates skin a lot. If it happens, wash with water and irritation will go away in 30 min or so. Use gloves.
Fill size 1 capsulles using capsule filler (quicker) or manually with piece of paper. Don't push DMF inside, just fill them gently till longer parts of capsule are full. When filled, close with shorter capsule parts and press gently. You should feel a click, and your capsule is sealed and ready to use. I usually make batches of 100 so it lasts for 50 days for me (taken twice daily).
Clean up, discard gloves and table protection, and that's it :)
Store at dark and dry place, away from heat, use pill bottle or something. Shelf life: Infinite :)