Macro to Copy Many Columns Contents and Combing them in 1 column

Was looking into this, but basically i have a repetitive task of copying contents from various columns, and pasting them into 1 column.

1 right after the other. I figured there could be a way for a macro to copy contents from multiple columns and paste them into 1 column.

I have including 2 files, 1 from the start of the file, and 1 how it should be so it will have clarify what i am trying to do.

So basically if you open book1 , i have factory install tabs,

I need the columns contents from the first tab the (5k-20k) starting with Column B, then E, then H, and so on( Every 3rd column starting with B ) to be copied and pasted in Column A of the (Factory Install Tab) ( last tab ).

If you open the 2nd file this will be clearly understood. In the second file in the factory install tab you will notice i did the first 2. I highlighted each starting part in yellow just so its easier to see. SO in column A you should have all the contents in the 5k-20k tab ( starting with b every 3rd ), pasted in column A 1 after the other.

The next tab is the 30k tab, i need all of the columns contents copied starting with B ( every 3rd again ), copied in Column C of the Factory Install tab. Basically every tab's contents needs to have its own column in the Factory Install tab.

If anyone could help that would be great, this is a very time consuming process manually, and it would seem like a macro could be made to easily copy contents.

Thanks