Is it ok to put an 8lb test line to a 12lb test line reel?

8lb test is just fine for trout. From my experience, pound for pound you'll break 8lb line easier with a 4lb trout than a 4lb bass. I don't use anything less than 8lb test. For your line, here's what I do when I spool it. I lay the spool on the ground (for spinning reels), then run the line through the guides and tie it on the spool. From there, I hold the line with a rag, and reel it on. I use the rag to put tension on the line as I reel so it's tight on the spool. As for rigs...it depends on how you want to fish. If you just want to bait fish, it's easy. There's only 2 main rigs you'll ever use. First is a bobber setup. Use a small hook (size 6 or 8) baitholder style, then put a bobber of your choice anywhere from 12" to 36" above it. I'd also use a couple small split shot (1/8-1/4oz total) to keep it down and cast further. The other is a slip sinker system. Use anywhere from a 1/4oz to 1oz (depending on depth of the water, how strong the wind is and how strong the current is) egg sinker on the main line. Then tie on a small swivel and another 12-36" of line with the same small baitholder hook as above. This works good for floating baits like powerbait or inflated worms, but you can also fish salmon eggs this way on the bottom. If you want to fish lures, which is more fun to me, i'd suggest getting a better setup, then getting some good tackle. Small crankbaits, jerkbaits, grubs, tubes, minnows, jigs all work. 1/16-1/4oz jigheads, small 2-3" tubes and grubs, 3-4" minnow baits, etc.

I have the same rod/reel. Are you fishing for trout? If you're talking about freshwater trout, that Tiger is going to be pure overkill. The reel holds 240-yards of 12lb line - if you used 8lb you'd be fitting around 350-yards of it on your spool and that's just too much. So you "can" put 8lb on your reel but it's not logical. I would run 12-15lb Berkley Big Game and use it for light saltwater (don't forget to rinse after) or cats/carp. Buy a smaller rod/reel for trout. I use mine for chucking dough baits for channel cats and carp, it does great for that purpose.

yes and you could even put 20 lb braid on there to

Well its cuz I'm kind of jus starting and I'm fishing for trout and people say 8lb is good. And my line is not tight. Its really loose. How do I tighten it? But for 8lb what kind of rigs should I use and weights and floaters?

8 pound is kind of heavy for most freshwater trout; it's OK or a little light for saltwater "trout". And it would be a bit awkward to fish with -- the rod has the pulling power for heavier line. To get the most out of any fishing gear, it should be balanced -- rod, reel, and line strength. Yours seems to be balanced for 12-15 pound line. One reason people use light line for trout (freshwater) is that you usually are using small lures or weights. Thick line will shorten your casts, as will a heavier rod made for casting heavier weights. If trout are your main target, see if you can return the outfit and buy a lighter combo -- one made for 6 pound line or so. The only way to tighten the line on the spool is to let it out (like behind a moving boat) and wind it back in with some tension on the line.