Conflicting advice on hp for multiclass

[ZorroGames]

Example only sorceror 1 - D6 max 6 hps and CO adds.

Later MC to to cleric (or Warlock or any other D8 class) does that first level of the new class get 8 and Con adds or only (roll or 5) plus Con adds?

Crux of discussion:

Is first level hp always as first level (max dice plus) or only the first level of your first class treated thusly?

[clash]

Only character level 1 gets max hp + con. Every other level regardless of multiclass is roll or take average.

"At 1st level, your character has 1 Hit Die, and the die type is determined by your c1ass. You start with hit points equal to the highest roll of that die, as indicated in your c1ass description. (You also add your Constitution modifier, which you'll determine in step 3.) This is also your hit point maximum. "

"Each time you gain a leveI,you gain I additional Hit Die. Roll that Hit Die, add your Constitution modifier to the roll, and add the total to your hit point maximum. Alternatively, you can use the fixed value shown in your c1ass enlry, which is the average result of the die roll (rounded up). "