Well. I did it, but only after cursing Record Power (wrongly).
The tyre is 19mm wide, rubber (not blue ... softer stuff).
Non-advice from Record (their gaffer promises a video soon):
1. Soak the tyres in hot (near boiling) water for 10 minutes.
2. Mount the wheels as shown, on scrap timber, on dowels, another holding a bit of copper / plastic tubing,
the purpose of which is to roll the tyre onto the wheel.
3. Clamp the tyre into the ... track of the wheel.
4. Brute force it round and on.
4a) Untried. Remember using fairy (dish soap) to ease on bike tyres? Try that?
5. Take wheel and copper tube off 'jig'
6. Mount in vice, ease the tyre down into the V of the wheel and ease any unequal pressure round the wheel, by rolling the tube and tyre all round the wheel.
7. Fit back onto the bandsaw.
8. Set up the blade, run a test cut.
9. Go get a drink of tea / wine / beer.
Facts: The new tyre is quite short compared.
The new tyre is like.... a hard thing.
If your old tyre is working.... stick with it.
If you're not quite strong in t'arm - get help.