ok ive never used this type of tremolo before

mainly cuz ive had a p.o.s. Behringer guitar/

i was wondering how to "lock" the bridge in place so i can downtune and all (ex. D standard, Drop C) but still be able to whammy up and down on it

because last time I dropped it the bridge went all the way back as if i was pulling it and yeah baaad buzz out of it.

so yeah can someone help me please? i really dont want to go to shop and pay someone to tell me how to do it.

Stick a piece of wood between the bridge and the guitar. and tighten the springs at the back (if necessary). You'll be able to do divebombs, but you won't be able to bring up the pitch.
ok that wasnt much of help really, i dont want to do that,
i still want to be fully able to use the trem. but just in drop c or etc
well, on my dropped guitars i use 11's. but if you're going to be changing the tunings alot, i would go with the heaviest you could find.
Would i need to make a truss rod adjustment since the guitar has never used those types of strings?