There are not so many couple dances done at eCeilidh events, it's not unusual to find a Rozsa waltz nowadays but the Ideal Schottische also has a well established place in the repertoire even if it is not quite as popular as it was previously
The music is an eight-bar hornpipe or schottische, so something twice as long as a normal French/Breton schottische. It can be anything from crisp and bouncy to slow and slinky
This description seems to have originated from some Hemlock Cock and Bull sleeve notes (All Buttoned Up, 1981) and appears as one of the couple dances in Brian Scowcroft's County Dance collection. (The Australian Heritage's Bush Dance pages include it and there's a variation on the Committee Band's It's about time CD)
Think Ballroom Direction as anticlockwise round the room, you'll hear it called the Line of Dance as well. This means that, the man is on the inside and the woman is on the outside, facing each other, and the man is going to head to his left and the woman to her right.
You are back-to-back and holding one hand and you want to get back to where you started...
This is where the music tells you what to do, with a crisp hornpipe you'll have no trouble doing steps into the middle.
With a more slinky Schottische you'll find the chassé variation easier
There a degree of ambiguity in the published descriptions of the dance:
This annotation made an executive decision that you let go of the leading hand after the first chassé. It is however often called that you let go of the 'trailing hand', for example as described in the Committee Band's It's about time sleeve notes. This means that you spend some time dancing backwards before you find you partner's free hand and it requires a little more space on the dance floor.
For smaller spaces and smoother tunes, the two steps into the middle and back out can make you feel like an elephant in a china shop. A Weberknecht variation is to chassé left and right again. This is smoother and at a stroke avoids the problems of having to remember which foot to start on when going into the middle (difficult) and the risks of colliding knees when you get it wrong (something which is all the more painful if you are dancing to an energetic hornpipe)
As mentioned, the music is an eight-bar hornpipe or schottische. 16-bar tunes do work but the 'typical' 4-bar French/Breton schottische tune won't help you enough with the phrasing, you won't hear when the A and when the B starts.
YouTube has Tickled Pink playing Green Potato where it's quite possible to see the effects of the ambiguity about which way to turn, with the dancers getting the swing of the dance by about halfway through.