1. Prep the oven so it heats to 425F, and set the rack in the middle of the chamber. Then, arrange the salmon fillets in a properly spaced manner inside a baking dish.
2. Mix the salt, garlic, maple syrup, and mustard in a small bowl, stirring, so it’s even. Then, generously spoon the spice mix all over the salmon.
3. Clove the container with foil and pass it into the oven. Then, let it cook for 15 minutes. Confirm doneness by poking a knife into the fillets. If the knife easily pierces them, they’re ready. You may notice a slight resistance, but it’s normal.
4. Gently remove the foil cover- it’ll be quite hot- and keep roasting the fish till the salmon flakes when poked with a fork. This tenderness should be obvious by eight to 10 minutes of baking. You can also confirm doneness by poking a meat thermometer in the fillets. And if it reads 145F, then the fish is ready.
5. Rest the salmon out of the oven and uncovered for three minutes. Then, serve as desired.

Also, see this video if you want more help.