As already noted, instant ramen noodles are a passable substitute for fresh ramen noodles, but the instant soup mixes are usually terrible.
For almost all standard ramen, start with a pork and chicken bone broth made with some leeks or scallions and very little else. For Kyushu-style tonkotsu ramen, boil very hard with lots of water to emulsify in as much fat -- especially marrow fat -- as possible; the soup should look like dilute milk at room temperature.
Seasoning depends on variety:
- Tokyo-style shoyu-ramen is mostly soy sauce
- miso-ramen is generally a dash of soy and then some mild miso mix -- white and red would be common -- worked into some of the broth and returned, as for miso soup
- tantanmen is doubanjiang (Sichuan garlic-chili paste), hot chili oil, soy sauce, and a big dollop of white or black sesame paste, all worked together with a little broth to dissolve
Garnishes vary widely, but often include:
- steamed baby bok choy or their leaves
- blanched bean sprouts
- sliced Chinese-style roast pork, usually very mild
- halved and shelled very soft-set hard-boiled eggs
- sliced scallions, negi, Kujo-negi, chives, etc.
- for tantanmen, ground pork stir-fried and caramelized dark with a little soy
Boil your noodles until just barely al dente: they should be softer than Italian pasta. Put a small ladleful of seasoning mix in each bowl, add a big ladleful of soup, add noodles, add garnishes, serve at once.
If you plan carefully, you should be able to make very passable ramen for very little money.