I'm trying to make a Barbarian subclass for one of my players, and I have 2 problems. 

The Lv 3 feature is spellcasting, I wrote down the whole spellcasting paragraph like told, chose sorceres spell list and CON as the ability score for casting, half level (Like eldritch knight), but when I go to make a character at the builder, it doesn't offer the spell tab at all.

The Lv 6 feature lets you choose 1 of 4 options, granting a different resistance to a magic type of damage, I inserted that there's only one option to choose from at Lv 6 (writing (6)) 
and it still doesn't work. 

any help will be very appreciated. 
https://www.dndbeyond.com/subclasses/960626-spellbreaker-barabarian

Eldritch knight is not “half level.” For one thing, it’s a 1/3 caster, not a “half caster,” and for another thing Eldritch Onoights don’t prepare spells at all. “Can Caet Spells”= yes, “spellcasting Ability” = Con, “Additional Spell List” = Sorcerer, “Spell Prepare Type” and “Knows all spells” = blank (put absolutely nothing in those two fields.

As for the option, don’t write “(6),” just “6” instead. Just put the number 6 and no punctuation at all.

After those two things, you MUST re-save the entire thing using the main [SAVE CHANGES] button under Basic Information or the system won’t pick up your changes.

I made sure to do all you said, and save, it still didn't change.
any more ideas ?

Double check your work because you must have made a mistake.

To add Spellcasting to a Barbarian requires:

• A feature named “Spellcasting” (not “spell casting,” it must be “Spellcasting.”)
• Under Basic Information:
  • Can Cast Spells = Yes
  • Spellcasting Ability = [any]
  • Additional Spell List = [any] (although Paladin and Ranger lack cantrips)
  • Additional Specific Spells = [any]
  • leave everything else absolutely blank

That’s how I made this: (https://ddb.ac/characters/56175468/sEubDo)

To properly set up options, follow the instructions I left in these threads:

• https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/67361-subclass-help#c4
• https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/68126-subclass-options-not-working

Assuming you've followed IamSposta's instructions, keep in mind it can take a little while for homebrew to update. On your test characters you may also sometimes need to reselect their subclass in the builder. It is basically the "have you tried turning it off and on again" of DNDB.

You could also try raising and lowering the level too.

I got it to work.
True I needed for it to wait to update, but it is a bit different.
When it comes to class\ subclasses that can already class spells, you're right (fighter is included due to Eldritch Knight already existing).
but when it comes to classes that don't have any option to cast spells like barbarian, you need to fill in all the options. (half caster and doesn't know all spells)
thank you for your help

No it doesn’t.

These would be “1/3 casters,” not “half-casters.” And they don’t prepare spells so that makes it unnecessary.