Are there any videos?
There should be instructions somewhere in your pattern, generally for a LT - knit into the 2nd st on the needle from the back, leave there while you knit into the 1st st normally, then let them both drop off the needle. For a RT, knit into the 2nd st from the front, then the 1st st. It’s like a mini cable and if you’d like to put the 1st st on a holder while you knit the 2nd one you can, but it’s faster not fiddling with the holder.
I’m making the Gingerbread Castle from the Walker 2nd treasury. There are no instructions in the pattern : ( .
One of the first rows that for example the LT stitch is used reads like this;
row 18-p7, k5, ssk, yo, k 10, LT, k8, ssk, yo, k7,p7
If I did choose to use a holder. How would I do the LT & RT with a holder?
For the LT, hold the 1st st to the front, knit the 2nd and then knit the 1st. For the RT, hold the 1st st to the back, knit the 2nd st, then the 1st. Once you do it a couple times this way, you might want to try it without, or at least practice it on some other yarn.
You can find videos for the twists on You Tube. There is one video there knitting cables without a cable needle. I also had this problem and posted it in here. Do a search on the twist stitich and you will see my post. Someone was kind enough to send me the video via this site.