Tie-nappy instructions
1.  Lay baby on the tie nappy and prefold or soaker-pad with the straps in front:

2. Fold up the prefold on the baby's tummy and then pull the back wings around on top of the prefold (not shown in photo)

3.  While holding the wings on top of the prefold with one hand, pull the front with the straps up on top and spread around to the sides:

4. Cross the ties in the back and bring them back around to tie them in the front:

With practice, you'll get a more snug fit around the legs.
You can add the Disana pull-on wool cover for a complete night-time system
which is very comfy for the baby, without and snaps or velcro:

Disana Organic Cotton Diaper-Wrap (Knitted Tie-Nappy)
One size fits all babies
These are great for night-time and very comfortable for the baby.  We don't use these as much in the daytime because they're a bit more work to put on than other diapers, but it is worth the little bit of extra effort for night-time.  I love that there are no snaps or velcro with this night-time system, making it very comfortable for the baby to sleep in.  You can lay a tri-folded prefold on the wrap and then position the baby so that the ties are in front (baby's head would be on the left side of the photo).  After folding the prefold up on the baby's tummy, then pull the stretchy back wings of the wrap around to the front on top of the prefold.  While holding that together with one hand, use the other to pull the front piece with the straps up between the baby's legs and over the wings/prefold.  Then wrap the straps around the back and then all the way around to the front again and tie them in a bow.  You can then add a cover on top such as the Disana pull-on cover.  With this combination you're almost guaranteed never to have a leak at night.   We have about 5 of these knit wraps so that we can use one each night and then wash them with the diapers every few days.

Disana Organic Cotton Diaper-Wrap (Tie-Nappies)
$17.95 set of 3