Step 1

Choose a site to grab from.

Step 2

Copypaste tags from the site you've chosen into the "Tags" field here.
Use "Advanced" search on sites (e.g. http://konachan.com/post/advanced_search) to generate some good tags.

Step 3

Choose limit value (how much links to grab) and page number.
Recommended value of limit: 1000 (100 for sankakucomplex). Maximum: 10000 (1000 for sankakucomplex).
If you want MOAR, you should increase page value and process request page-by-page.
Example: if you want grab 20k links, the best way is to request 4 times with 5k limit per page. Otherwise you may as well get nothing.

Step 4

Press the "Process" button... and wait. If you dont get any results - try again.

Step 5

???

PROFIT!!