DES encryption

Hi. I've been reading up on DES encryption (and 3DES) and found a few websites explaining it all but I have a few questions. (Not sure if this is the right place to post :/ )

All the sites that I went through that explain it in detail all use the same data, like the tables and such. This may sound stupid but any table can be used for the permutations of the data right? Like if I make my own?

Or is there a reason that the same tables were used?

Also, this only works on 64-bit blocks, so if I wanted to encrypt data that was larger than 64-bits, I would just split it into 64-bit blocks and apply it right?

PS: I want to try and make my own implementation of DES :rolleyes:

I don't know a lot about encryption, but if you want to encrypt blocks of data larger than 64 bits, try looking up "modes of operation" for block cyphers.