I started making fresh sausage this past spring.
Buy a mix and follow the instructions. Certainly for the first time. Making sausage isn't really like following a recipe. There is more to worry about than the ingredients that go in. Like, what should my bind be, do I need more water or less water? How "full" should casings feel? I think this is full, but when I cook them, they're not full at all.
When you follow the instructions in a kit, it'll tell you how much water to add and you'll get a good feel for how the meat bind should feel before it goes into the casing. Also, you'll know it's safe and won't have to worry about if you need a cure or how much.
When you're comfortable that you can physically turn out a good sausage (don't worry, all those "mistake" batches are still good eating), then start developing your own sausage. Just learning about how sausage making uses weights and percentages takes some study. Look at any "recipe" that uses measurements for ingredients with a suspicious eye. Tablespoons and teaspoons aren't the language of sausage making.
This is one of my favorite sausage recipes. It is a Central Texas-style beef sausage (despite the fact it has pork in it) and comes courtesy of one of the moderators of the r/bbq sub-reddit. It was my first "from scratch" sausage and it was awesome:
100% Beef
30% Pork
6.5% water
1.75% salt
1% cafe grind black pepper
1% paprika
.0025% cure #1
Pork is optional, but greatly improves the sausage. Double grind all meats through a 6mm plate. Use brisket trim for the beef, pork shoulder for the pork and don’t worry about the fat ratio. Trim nothing.
Smoke at 200f until 155 degrees IT, chill in ice water bath. Before service smoke at 275 until 165 it, slice and serve.
Good adjuncts are cayenne, 8% jalapenos, 8% sharp cheddar cheese...etc
If you’re having problems with your bind you can add in up to 3% dry milk powder (1.5% will probably do it). It doesn’t affect flavor.
