Hi,
HikaSerial can be used to generate coupon codes upon the purchase of products.
So I don't think you need HikaSerial to do what you want.
I think you can do it just with HikaShop.
To import coupon codes to HikaShop, you can use the CSV export/import features of your phpmyadmin on the hikashop_discount table.
Create one or two coupons via the HikaShop coupon interface and then export the hikashop_discount table once to look at it with Excel or LibreOffice Calc. In there, you can then add your rows or additional coupons in the same format than the coupons already listing in the CSV. Note that you'll need to enter the user id from the hikashop_user table for each coupon in the discount_user_id column so that each coupon match with the corresponding user account. Then, when you import back the CSV, you'll get all the coupons in HikaShop.
If you don't mind the format of the coupon codes, then you could get an export of the hikashop_user table to automatically fill the discount_column with the user_id and/or a piece of the user_email table so you would be able easily generate all the coupon codes in Excel without having to manually associate each one.
