Generally printmakers 'pull proofs' before launching into the final print run. It's a good idea to test your print on scrap fabric or paper to see if you like the look of it, because more cutting might be required. But this one's fairly predictable...
Pick the inked block up by the edges, turn it over and plop it onto the fabric. (Try not to get ink on your fingers like I've done). If you're doing a rigid repeat or using more than one colour, you'll probably need to mark out some positions using a water-soluble pen. Here, I'm just winging it.
(The fabric is zig-zagged around all the cut edges because I wash everything before printing - new fabric to remove sizing that might interfere with ink take-up, and old fabric because you never know where it's been.)
Apply pressure. Just lean on the block if it's small enough, or use a roller if it's bigger than your hand. Hold the block in place with your other hand for the roller method (tricky if you're taking pictures as well).
Lift the block straight off so you don't smudge the print.
And then just keep going....
The paint should dry to the touch quickly, as it's only a thin layer. The next step is to cure the fabric so that it's washable. Instructions should come with the fabric paint, or at least be on the manufacturer's website, but just in case: most fabric paints require heat setting. Apparently this can be done in a tumble drier, but the safest way is to iron the print from the back on the highest setting your iron has. Work slowly across the fabric, stopping just short of scorching it. You might see steam coming off - that means it's working.
Fabric can also be cured in the oven. Set the oven to 180 C (356 F) and fold the fabric with the printed surface on the inside. When the oven is hot, turn it off, place the fabric on a baking tray, stick it in the oven, and walk away. 5 minutes is supposed to be sufficient; I'm more comfortable with 10. I'm also paranoid, so I give the fabric a quick once-over with an iron as well, just to be sure.
If you've marked positions with a pen, dunk the fabric in water for a few moments to remove the marks. You'll be able to check if the paint has cured properly, too, because uncured paint goes slimy in water.