What did the dragon give the beast, and what does that mean?
The dragon, identified as Satan, gave the beast his throne, his seat, and his authority. This signifies Satan empowers and legitimizes the beast's rule, so the man rises on the world scene satanically driven, wielding delegated authority that is not his own.
Les explains that the dragon is Satan, and the beast is the coming man. Satan gives him his throne, his seat, and his authority, so the man's rise is not merely human but satanically driven. Earlier in the same context, Les notes this figure will achieve his end by lying, deception, flattery, and a charismatic personality, drawing people to fall at his feet, even though he is corrupt. Thus the beast's power and rule are delegated from Satan himself.