Hey Dakota, glad to see that you're developing an interest in Ringen as well as the sword. For training in Ringen, the biggest help you can get is to get a training partner, that way you can practice the techniques on an actual person, but with restraint obviously so you don't hurt them. Other than that, a good punching bag is good enough for strikes. You might also invest in a throwing dummy so you can get practice in completing throws.
As for manuals, I would suggest the Codex Wallerstein for techniques, as it has the largest selection of techniques in a single manual, except for maybe Mair or Meyer.
Remember that Ringen is predominately a grappling or wrestling style, not a striking one. However, strikes are present and do have their place. The idea is to strike to stun your opponent, then wrestle to finish him/her. But if you see an opening for a wrestling move from the get-go, go for it.
When it comes to starting out, learn the guards for Ringen first, there aren't many but there are a few. The Pisani-Dossi version of Fiore dei Liberi's Flos Duellatorum shows four unarmed guards, one of which is mirrored in Talhoffer. And the Codex Wallerstein describes a fifth in it's text.
Then learn the strikes, as they are the basis for most of your wrestling. I have here a list of all the striking combinations that I have uncovered with their sources:
1. Jab to the Face, Cross to the Face (Article on ARMA website)
2. Cross to the Face, Jab to the Face (Article on ARMA website)
3. Cross to the throat, Grab, Cross to the Solar Plexus (Ringeck)
4. Cross to the throat, Grab, Knee to the Groin (Ringeck)
5. Cross to the throat, Grab, Right Hammerfist to the Temple (Ringeck)
6. Cross to the throat, Double Hammerfists to the Neck (Ringeck)
7. Jab to the throat, Cross to the Stomach, Hip throw (Ringeck)
8. Ear Press, Cross to the body (My interpretation of Codex Wallerstein Plate 32)
9. Double Hammerfist to the Neck (this is a feint), Knee to the Groin (CW Plate 133)
10. Ear Press (this is a feint), Hooking Sweep to the Legs so he falls (CW Plate 139)
11. Jab to the throat, Slip, Cross to the Stomach or Single Leg Takedown (CW Plate 132)
12. Parry, Front Kick to the Stomach (CW Plate 134)
13. Parry/Grab attacking arm, Cross Punch (I've seen this in Talhoffer but can't remember where at the moment.)
But to reiterate, wrestling is what truly finishes your opponent in Ringen. As such I would work with a partner on grappling most of all. If you can't find a partner, try to get a throwing dummy. Also, I have found that a rope or belt tied to a post can allow you to get some practice with armbars or joint-locks.
But one vital thing that I would finish with, go to this page:
http://www.thearma.org/essays/ringen-vocabulary.pdf
It has a list of the most commonly found techniques along with the images those techniques were found in.
As for other training methods, I'm sure there is much more than what I have mentioned and I heartily encourage anyone else to add what they've found effective for them.