First of all I have to say that in my opinion you cannot actually train a puppy until it is old enough to understand what you want it to do which is generally 16 weeks of age. At 8 weeks of age your puppy is still a baby. Can you imagine potty training a 6 month old human? It simply is not feasible. I do believe that you can create a habit in your puppy by having pee pads available for pottying on. The puppy will get used to feeling the paper on its feet when it goes potty. What happens when the puppy is out of the pen? Look out rugs! They will go potty when they feel something familiar on those little feet. That is not training it is habit. Puppy has not learned to potty only on its paper but on something that feels familiar. Or puppy may just go wherever and not look for anything under its feet at all.
When you first bring your puppy home do not worry about potty training. Expect to have to clean up after your puppy.
A miniature dachshund is not that big and hence neither are its puddles and piles. Just pick it up and flush it. There will be plenty of time to train once your puppy is well settled into its new home. If you don't want all the clean up maybe you should get your puppy at an older age? Say 10-12 weeks.
This is what has worked for me in my home. I have a folding pen that has 8 panels that are 2' x 2' squares. I fold it down into a 2' x 4' pen. I use a plastic carpet protector underneath as flooring to protect my vinyl floor in my kitchen. I then place a plastic puppy pad holder at one end (additional floor protection) and a tiny crate or some form of bedding at the other end. I place food and water bowls at the same end as the bedding area which encourages puppy to keep its bedding area clean. Pick up any piles as quickly as possible. Puppies are quick to step in their piles and then you have feet to wash too.
I like my dachshunds to eventually be trained to go potty outside. I do not want my puppy on the ground until I feel it is fully immunized. Usually at 14 weeks of age I start taking my puppy outside on a regular basis. I set up a small pen so I know if puppy has done its business. This also keeps puppy from getting into trouble or wandering away. When I see puppy going potty I immediately praise him. Puppies and dogs have short term memories so it is very important to give praise or correction while he is actually in the act. Take your puppy out first thing in the morning, after eating and upon waking from a nap.
When your puppy is out of its pen make sure you are keeping an eye on him. When you catch your puppy in the act of doing something he shouldn't make a disapproving noise, quickly pick him up and either put him on his paper or take him out to his potty spot.
Be consistent and all will eventually