You use the 2da line number (the leftmost number), as all consts do. Take a look at the nwscript core include to see the default consts and compare them to 2da values. I suggest you add new consts in a different file, though, if you want to use them (for, say, ease of readability).
For an example of how to declare your own consts, here's an example file from the legendary leveler showing both const strings and const ints. You'll be using const ints for your damage types:
// This lists all of the constant ints that are to be used for LL
// This is the path to your servervault. It must be set correctly for Letoscript to work.
//const string NWNPATH = "C:/NeverwinterNights/NWN/servervault/";//windows sample
const string NWNPATH = "/home/funkyswerve/nwn/servervault/";//linux sample
const string NWNPATHDEV = "/home/funkyswerve/nwn-dev/servervault/";
const int ALSO_USING_DAR = TRUE;//set this to true if also using DAR subrace system
const int DEBUG = FALSE;//set this to TRUE to enable debugging
const int DEV_CRIT_DISABLED = FALSE;//set this to TRUE to disable devastating critical feat selection on levelup
// Experience Requirements for Legendary Levels
// Adjust as desired. These were set by increasing the additional amount required for the
// previous level by 25%. Level 40 required 39000 experience points, so Level 41 was set
// to require 39000 x 1.25 = 48800 experience points under the old system. This will be ALOT on some worlds,
// and not enough on others, so adjust to suit your needs. Under the new system the progression is a linear
// rather than an exponential increase in the additional amount needed per level.
const int BASE_XP_LVL_40 = 780000;//220 //780000
const int XP_REQ_LVL41 = 1000000;//240 //828800; //48800
const int XP_REQ_LVL42 = 1240000;//280 //889700; //60900
const int XP_REQ_LVL43 = 1520000;//320 //965900; //76200
const int XP_REQ_LVL44 = 1840000;//360 //1061100; //95200
const int XP_REQ_LVL45 = 2200000;//400 //1180100; //119000
const int XP_REQ_LVL46 = 2600000;//440 //1328900; //148800
const int XP_REQ_LVL47 = 3040000;//480 //1514900; //186000
const int XP_REQ_LVL48 = 3520000;//520 //1747400; //232500
const int XP_REQ_LVL49 = 4040000;//560 //2038000; //290600
const int XP_REQ_LVL50 = 4600000;//600 //2401200; //363200
const int XP_REQ_LVL51 = 5200000;//640 //2855200; //454000
const int XP_REQ_LVL52 = 5840000;//680 //3422700; //567500
const int XP_REQ_LVL53 = 6520000;//720 //4132100; //709400
const int XP_REQ_LVL54 = 7240000;//760 //5018900; //886800
const int XP_REQ_LVL55 = 8000000;//800 //6127300; //1108400
const int XP_REQ_LVL56 = 8800000;//840 //7512900; //1385600
const int XP_REQ_LVL57 = 9640000;//880 //9244800; //1731900
const int XP_REQ_LVL58 = 10520000;//920 //11409700; //2164900
const int XP_REQ_LVL59 = 11440000;//1060 //14115900; //2706200
const int XP_REQ_LVL60 = 12500000;//17498600; //3382700
Funky
