Help Needed! Appending 2 tables creates empty columns

Hello everyone here, and nice to be part of your community!

I'm working on a PowerBi file and I'm trying to append 2 tables with 3 columns each, but the result is a table with 6 columns ( the top half of the table has the first 3 columns with data and than other 3 columns with "null" data, meanwhile the bottom half of this new created table has the first 3 columns with "null" data and the next 3 columns with the real data in it... Why is that happening?? I did it several times, but the result will not change....

I just hope I managed to explain my problem somehow...

What should I do??  

Thak you so much in advance!

This is my first table...

This is my second table...

And this is the result...🤔   ...   I swear I used the "Append" button and not the "Merge" one!!

....the second half of my appended table: