Summarize simple use of Power Query for impatient experienced user with simple need?

I'm a longtime Excel user, comfortable in using it for all kinds of text manipulation and basic number crunching, beginning to get a handle on tables and new 365 formulas. I've learned most of what I know from self study and enjoy it, but at the moment I'm a bit overwhelmed with trying to get started with Power Query. It seems like just the tool for what I need to do, but it's also designed for a lot more, and I'm having trouble getting my bearings since even the basic introductions assume that my needs are much more complex than they are and talk about a lot of options that are irrelevant to me.

This is all I need to do:

I have a workbook with a table where I keep track of work on inquiries sent to an online platform from which I can export submissions into Excel. The export contains a few columns I don't need, and lacks a few others that I add in the workbook, so what I've been doing is opening the export file, deleting unneeded columns, adding blank rows to the bottom of the table, copying the data from the export file, and pasting it in beginning with column D.

Seems like just the kind of thing to automate with Power Query. But I don't want to keep the export file anywhere once I've appended its contents to the workbook. The data remains in the online platform if I need it, and storing any subsets would only waste space and cause confusion. I want to export the latest submissions, transform them with Power Query (I've already figured out how to do that), append them to my workbook, disconnect the two files, and delete the export. Sounds simple enough. But I can't seem to find out how to do this very simple thing without having to sit through long explanations of things I don't need to do and am too busy to wrap my head around right now.

Can anybody point me to some simple step-by-step directions that just tell me how to do only what I need to do without bothering with all the other possible scenarios? Or is Power Query overkill for my needs? Is there another alternative?

Thanks.