This video demonstrates importing transactions into Wave Apps. I also talk about some issues surrounding this topic.

Wave also has some troubleshooting tips for importing CSV files:
https://support.waveapps.com/hc/en-us...

0:00 Intro
0:08 Discussion of Wave pricing plans
1:17 Transactions page - 3 options to import
2:07 Brief mention of chart of accounts
2:28 Downloading bank and credit card transactions
4:32 Uploading transactions into Wave - QBO format
6:18 Money between accounts (watching for duplicates)
7:15 Uploading transactions into Wave - CSV format ex 1
11:44 Uploading transactions into Wave - CSV format ex 2

Disclaimer: This video is not intended to replace advice from your CPA or tax preparer.