You're in for a new, wonderful experience. I became the caretaker of a Manx 2 1/2 years ago and she has been a joy. Most info on the breed says they are more like a dog than a cat and I have to agree......except she does have the 'cat attitude'. :)

On the scratching issue: supply the cat with several options and place them in areas it tends to hang out. When I first got my cat (abandoned kitten) she hung out below the TV so I placed toys and cardboard scratchers there along with one under the dining table. The tall scratching post has moved around the house but it's now in an area she strolls by every morning. I would also recommend you buy a tunnel.......a great 'toy' for cats.

There will be the kitten stage, no way around it, where it's going to be everywhere and testing everything. Keep a spray bottle handy and be ready to give a squirt when the kitten is somewhere it shouldn't be. But, give a warning first. I quickly realized my kitten would respond to 'no' of 'off' so I rarely needed to use the squirt bottle.
At one point I had to purchase Static Pads to keep her away from the LR furniture. I used them for about 3-4 months and haven't needed them since. She'll only scratch at a chair now in order to get my attention (if I'm on the computer) if she wants to be fed.

On cat litter: I've tried several brands and always return to unscented Worlds Best. Everclean has too much of an odor (even the unscented) and odors can often cause cats not to use the litter box. You'll find that you'll go thru different sizes of litterboxes. My kitten was so small she started off with a shallow pan and she now uses one of the largest boxes sold at Petco!

Best money I ever spent was on cat trees. If you play with it on it, scratch it yourself. The scratching sound incites them to scratch, too.

You may need to try out different types of scratchers. I've had one cat who liked a scratching post. The others all went for the cardboard scratchers, which are flat to the floor.

During the kitten stage, if your kitten ends up wanting to scratch everything in sight, you may need to cover your furniture with sheets or blankets, until the cat is trained to use the scratchers. A loosely draped blanket isn't usually a good scratcher for a cat--they need the fabric to be pulled tight.

I had one cat who loved to scratch one chair. I sort of sacrificed that chair to him--it's in shreds. After he's gone, I'll get it recovered. I do not recommend this approach, however.

Use a stern 'NO' and if that doesn't work, use the spray bottle. Some cats respond to discipline immediately and it only takes once and others ---- not. Just be patient and be sure you always take the kitty to the scratching pole immediately so it knows where it can do this.

Our 7 cats are inside/outside and have all learned not to scratch furniture. (Only 4 know for sure to stay off counters though) but then they all have the option to go outdoors to use their favorite scratching places (and bathroom).

Our biggest discipline problem is keeping them from jumping on the screens when they want to come in.

Training, training, training ... I'm always amazed at how many people think cats can't be trained. Use some of the methods described above and keep it consistent.