First off welcome, if you haven't yet head on over to roll call and put up a post so you can be greeted proper by the community.
First off what equipment do you have? You can make venison sausage pretty much with a small hand crank meat grinder with stuffing tubes and nothing else. A sausage stuffer is a great investment, but maybe you should start with something smaller first that can do it all, and eventually move up.
From there, you either need a good recipe or a premade mix. Either or should include a cure (commonly known as instacure #1 or the pink cure salt). Measure your meat, spices, and cures accurately always, for me a digital kitchen scale was a great $30 investment. Always mix the proper amount of meat to cure ratio, never under, never over. Cure must be measured precisely to keep everything and everyone safe, but as most things in life if you are accurate with your measurements its very easy to use.
I order all my spices and casings from midwesternresearch.com, but there are lots of places to order from. I get the 3" diameter mahogany fibrous casing, and use the h blend Excalibur summer sausage seasoning....and have been told many times my venison summer is "the best they have ever had". I will get into doing my own recipes someday but the spices are priced good and I really like the flavors so far and have made quite a few of the excalibur blends. Alot of times I will add some extra pepper to the recipes because I like things hot, in the case of summer I add about 1/2 cup of whole peppercorns to a 25 pound batch
When making a venison sausage, you almost always need to blend in fat because the venison is just so lean. Most say shoot for 10-20% fat content, normally 10% is about as fatty as I go because I like lean sausage. I mix ground pork or straight pork fat in mine that I get from trim when we butcher hogs (we do all our own processing in my family). Alot of people just buy a pork butt, bone it and grind it, and really thats a great way to go as well. Most butts are around 40% fat content, so mixing 75% of lean venison with 25% of a 40% fat content pork like butt shoulder will give you round 10% fat content in your finished product, which is perfect as far as I'm concerned. You can find a program on this forum called the sausage makers square that will help you figure percent lean for sausages.
Once you have the meat end of things figured out, mix your spices and cure packet with enough water to just liquify it, pour over the meat and mix very well. I always mix about 5-10 minutes after I am darn sure I have it mixed well. You will feel the meat start to change texture as you mix, the cure starts to take hold and the meat will get a very sticky and tacky texture. Unless you have a good sausage stuffer, this is the point you want to stuff the casings. I wet my fibrous casings down and then stuff them tight....spin them off tighter, then tie off with a good cotton or hemp twine. Then put in the fridge overnight on a towel to dry and complete the cure.
Next morning they go into the smoker. Sausage is never something you want to rush in my opinion. I start mine at about 110 or 120 for a couple hours to dry further, then hit them with a heavy smoke, increasing about 10-15 degrees in smoker temp per hour until I reach 180-185 tops. I use alot of TBS for about 5-6 of those hours using hickory, and that suits my taste just fine. The fibrous casing is tough to penetrate with smoke flavor. Normally the meat will take between 10-12 hours using this method, meat is done when internal temp is 152. Notice that you can smoke for long periods in the meat danger zone of 40-140 degrees....this is because you add the cure and it destroys the botulism and other nasties in the meat overnight when you let it cure.
When you are getting close, fill tubs with either snow and water (I like to do summer in snowstorms and the dead of winter). The sausages go straight from the smoker into an ice water bath until internal temp is 110 or below (I usually take mine below 100). They then come out of the ice bath onto towells at room temp for several hours until the desired bloom or sausage fullness is achieved. Doing it this way assures you don't get a shriveled product.
At this point you can keep what you want out, wrap the rest in either a vacuum packer or good freezer paper and freeze. It will last a long time if protected from the air, but for some reason 25 pound batches tend to disappear in a week or two with my family of hunters!
Good luck, you came into a great community and there is a ton of information here if you take the time to read and look and very helpful friendly people.