If importing from deckbox this is what you need to do.

Step one:

Deckbox puts a bunch of extra columns in. Deckbox also just says the word “foil” in one column if you have a foil version. It doesn’t give you a quantity You need create another column called “foil qty”. Then go down through your list and each one that says “foil”, transfer the number of foils you have to your new “foil qty” column for the corresponding card.

Step 2:

Download the Echo MTG example template. You will need to edit the example template itself, and then upload that. Add an amount of horizontal rows to the example template equal to the number of horizontal rows listed in your deckbox cvs. Then hold down the mouse button and scroll down to copy the data in each column. Paste the data from each column into the corresponding column of the example template. Then upload the example template to Your Echo MTG inventory.

I uploaded almost 22,000 cards and it was very accurate this way. I have a Mac and use the “Numbers” program instead of excel.

Thank you Discord Member CalebRyder for the tips above!