I'm gonna be running a Ravnica Campaign, but I can't figure out for the life of me how my PCs are able to assign their guilds to their characters and gain access to their accompanied expanded spell lists in the DND Beyond Character sheet, this is especially big for an Izzet Wizard build a player has their heart set on for Chaos Bolt and Heat Metal. Assistance, or lacking that, Devs here's something that you really should address, it's been about a year since the thing was released!

Adding the guild backgrounds adds the spells to your class list, although the character builder doesn’t show that when previewing them.

Thank you sirrah! It would be very good if the spell lists were separate from the guild backgrounds, because some players want a separate background and having only recently joined their guild.

Quote from QuillScroll >>

Thank you sirrah! It would be very good if the spell lists were separate from the guild backgrounds, because some players want a separate background and having only recently joined their guild.

 You can make a homebrew background starting with a copy of the guild background to get the spells. The planned general features system might be a good place to put guild spells in the future.

Is there any update on adding the Background spells to the Character sheet yet?

Quote from Almondschocie >>

Is there any update on adding the Background spells to the Character sheet yet?

 
The feature is fully working as intended. If you add the Guild background the relevant spells become available through any spellcasting class you may have. You may need to refresh after adding the background to get the spells to appear.

The issue is there are characters that aren't of the guild background but join the guild later

Rules as Written do not allow backgrounds changing.

However, if the DM allows it, the player (or somebody who owns the backgrounds) can make a homebrew copy of their current background and add the spells into the "additional spells" box. Rename background to append the guild name, and then use that background.

You're not quite picking up what I'm putting down...a PC does NOT have to have the guild background to join that guild, in fact, some campaigns it's about choosing what guild to join, instead of starting in one, so they have to tale different backgrounds. The issue is there's no way to just get the guild spells regardless of background. You don't have to have your character start as an izzet engineer to join the izzet league

Quote from QuillScroll >>

You're not quite picking up what I'm putting down...a PC does NOT have to have the guild background to join that guild, in fact, some campaigns it's about choosing what guild to join, instead of starting in one, so they have to tale different backgrounds. The issue is there's no way to just get the guild spells regardless of background. You don't have to have your character start as an izzet engineer to join the izzet league

 
Please read my post carefully. I am not saying the player has to have a ravnica background, I'm saying they can edit whatever fluffing background they have and just add the spells into the box. This way they get the guild spells and keep whatever background they chose, be it Sage or Acolyte or Urchin or whatever,.