The guidance in the TB is intended only for generators with rated output 15 A or greater. If you only have one with rated output less than 15 A, or that only has 10 A sockets for connection; you can’t use it under this TB.
And if it’s a “larger” connection; you must get a specific design by an Inspector or Electrical Engineer. “Larger” has not been defined; but all multi-phase installations are deemed to be “larger”. For single-phase; it would be wise to treat any connection intended to carry 32 A or more as “larger”.
This design work may not be a “certified design” (as per ESR 58); because it may not be specific to one site. But what we’re doing would normally be what’s called a “Part 1 solution”; so it certainly makes sense to get another brain involved in working out how to do it .
Note that it’s the rating of the connection that counts; not the maximum output of the generator. So if you have a large genset available, but are inly using it to supply a small load; you don’t need a special design. You may even be able to use a single large, even multi-phase, genset to supply several installations