How you create your DB depends of the S5-version that you use.
At this moment I do not have installed S5-software anymore but if I remember this correct for one of the latest versions you need to open the second menu on the left and then you have to choose 'create DB'.
The header contains information about the type of data-word, like 'KF', 'KH' ect. and also comment. This stays on your harddisk and is not transfert to the plc.
S5-DB's are always global DB's. You can only open one DB at a time. If you want to use the DB, first you need to adres the DB. I always used the german version. For this the STL-instruction is 'A DBx', for the later versions you can also use a LAD-instruction like with S7.
After this you need to 'load' and 'transfer'. There is no MOVE-instruction, only a 'L'- and 'T'-instruction. Example
A DB1 //adres DB1
L IW 0 //load input-word 0
T DW0 //transfer to dataword 0
L IB0 //load inputbyte 0
T DR1 //transfer to Rightbyte of Dataword1
L IB5 //load inputbyte 5
T DL1 //transfer to Leftbyte of Dataword1
Datawords are adressed with word-adresses. If you want to adres a databyte you need to use 'DRx' or 'DLx'. This is Dataword-rightbyte and dataword-leftbyte.
You can not adress seperate bits of a dataword. Once a DB is adressed it stays adressed untill you adress a different DB or if the block in witch the DB is adressed has ended.
