I won't waste your time with a long intro, here's how to bulk import links. 

Importing:
Within a column, click on the three dots followed by 'Import & Export'
You can now add one or multiple links 
You can a-sign a name to the card as well by adding "| Card name" 

Ex: 
Unnamed: https://producthunt.com
Named: https://producthunt.com | Product Hunt

You can now import your links from OneTab in just a few clicks:

Visit One tab > Export
And use the above popup to import your data.

NEW: You can now bulk edit bookmarks as well. Here is how:

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