For tinning, my cheap home method is to coat the traces with a flux pen as soon as the board is finished etching, then run all over them with the thinnest coat of solder from my iron.
I've drilled them before and after the flux and or tin process and usually prefer to drill before fluxing.
I too use tin snips for cutting my boards, sometimes sanding the edges with 600 grit wet and dry paper with water and a little soap to get a nice smooth edge.
Conformal coating is available to coat and protect your board. I'm planning to give polyurethane varnish a try on my next project.
First, what you call paper isn't paper, it's a type of plastic! There's a possibility that it will melt if you try to transfer it using clothes iron.
Next, the document for the board doesn't mention that it's covered by anything, but if it actually is and you really want to use toner transfer, you'd need to get rid off the cover using developing solution. If you manage to get the real datasheet for the board, you should be able to get recommended solution there. I just use 10 g of NaOH in 1 l of warm water.
You also need to expose the board as well. First a quote from Wikipedia:
Photoresists are classified into two groups: positive resists and
A positive resist is a type of photoresist in which the portion of the photoresist that is exposed to light becomes soluble to the
photoresist developer. The portion of the photoresist that is
unexposed remains insoluble to the photoresist developer.
A negative resist is a type of photoresist in which the portion of the photoresist that is exposed to light becomes insoluble to the
photoresist developer. The unexposed portion of the photoresist is
dissolved by the photoresist developer.
You need to get documentation for your board or try your luck and determine if you need to expose it before developing or not. If you do need to expose it, just leave it in the direct sunlight for a few hours and then drop it in the developer. After it's developer, rinse it in water and the photoresist should be gone.
If the other side is not coated, I don't see a reason why it wouldn't work well for toner transfer.
After that, you need right paper, right clothes iron (or laminator) and right printer. That's why there are so many recommendations! Different combinations of those will provide different results.
I haven't experimented with magazine paper yet, but from my experience the thicker and glossier paper is, easier it will be to transfer the toner from the paper to the PCB. Also you need a good heat source to transfer the toner from the paper to the PCB.
In my experience, if you don't know what you need, go for FR4. Currently it seems to be the "default" PCB material.
Finally, since you said you don't have any resources locally and aren't in a rush, consider ordering a done PCB. It will be probably be cheaper than complete investment of making the PCB yourself.
In the PCB industry this is called component potting.
The white ring is there to ensure the pouring of the resin can reach the required height and not spill on the nearby components. What component is under there is tricky to know but you can make educated guess:
For me looking at the size of this I would tend to say it is a trimming potentiometer that was sealed after calibration, the white ring being there to ensure the resin was poured high enough. The resin making the calibration more permanent than anything else (that is maybe why they have gone with this instead of a dab of glue).
This might be entirely wrong, I am not the one who designed this.
From the extanded details of the later answers and comments ! It is clear that I was wrong... I think we can now confortably assume that the potting was done as a sound insulating feature to reduce audible noise from the SMPS (that was the ahah factor I think).
That was a very good question ! I definitely learned something new. And I wish more powersupply manufacturer would implement these.