Phil. please what we need now to add something to the script to multiplying the final value x20. It is because the value is %, I think that will be better, if it is shown as a number i.e. 70% = 20x70=1400

If I'm understanding right, that's a simple modification to the script,

var pieces = /(-?\d+?),(\d+).*/.exec(p.value);
return parseFloat( pieces[1] + "." + pieces[2] ) * 20; //multiply it by 20

You could automate creating the meta points by doing something like I did in this thread, https://forum.infiniteautomation.com/topic/2473/how-to-bulk-import-event-detectors

It's probably possible and perhaps easier through CSV export/import, but I would do it with a script like,

var xidPrefix = "N_"; //used to create a unique XID from the XID of the data point, chose N for numeric
var snmpDataSourceXid = "DS_c4248bb3-9877-4ed7-b228-0bd08c3f77b6"; //Identify the points to add to, change to your SNMP DS's
var metaDataSourceXid = "DS_b9d9db6b-49f3-4c92-820d-7f2a65c39ea4"; //change to your meta DS

var dataPoints = JSON.parse(JsonEmport.getConfiguration("dataPoints")).dataPoints;
var snmpPoints = DataPointQuery.query('eq(dataSourceXid,'+snmpDataSourceXid+')&limit(1000)');
var createdMetaPoints = [];

function findByXid(list, xid) {
    for( var k = 0; k < list.length; k+=1 )
        if( list[k].xid === xid )
            return list[k];
    return undefined;
}

function createMetaPointForDataPoint(dp) {
    if(findByXid(dataPoints, xidPrefix + dp.xid) !== undefined)
		return; //ensure we don't create the meta point twice
                        // but it would just import and save again, no biggie
    
    var meta = { //Gotten by configuring one and exporting it
         "xid":xidPrefix + dp.xid,
         "name": dp.name,
         "enabled":true,
         "loggingType":"ALL",
         "intervalLoggingPeriodType":"MINUTES",
         "intervalLoggingType":"AVERAGE",
         "purgeType":"YEARS",
         "pointLocator":{
            "dataType":"NUMERIC",
            "updateEvent":"NONE",
            "contextUpdateEvent":"CONTEXT_UPDATE",
            "context":[
               {
                  "varName":"p",
                  "dataPointXid":dp.xid,
                  "updateContext":true
               }
            ],
            "logLevel":"NONE",
            "variableName":"my",
            "executionDelaySeconds":0,
            "logCount":5,
            "logSize":1.0,
            "script":"var pieces = \/(-?\\d+?),(\\d+).*\/.exec(p.value);\r\nreturn parseFloat( pieces[1] + \".\" + pieces[2] ) * 20;",
            "scriptPermissions":{
               "customPermissions":"",
               "dataPointReadPermissions":"superadmin, edit-ui-menus, edit-ui-pages, edit-ui-settings",
               "dataPointSetPermissions":"superadmin, edit-ui-menus, edit-ui-pages, edit-ui-settings",
               "dataSourcePermissions":"superadmin, edit-ui-menus, edit-ui-pages, edit-ui-settings"
            },
            "settable":false,
            "updateCronPattern":""
         },
         "eventDetectors":[
         ],
         "plotType":"SPLINE",
         "rollup":"NONE",
         "unit":"",
         "simplifyType":"NONE",
         "chartColour":"",
         "chartRenderer":{
            "type":"IMAGE",
            "timePeriodType":"DAYS",
            "numberOfPeriods":1
         },
         "dataSourceXid":metaDataSourceXid,
         "defaultCacheSize":1,
         "deviceName":"Parsed " + dp.deviceName,
         "discardExtremeValues":false,
         "discardHighLimit":1.7976931348623157E307,
         "discardLowLimit":-1.7976931348623157E307,
         "intervalLoggingPeriod":1,
         "intervalLoggingSampleWindowSize":0,
         "overrideIntervalLoggingSamples":false,
         "preventSetExtremeValues":false,
         "purgeOverride":false,
         "purgePeriod":1,
         "readPermission":"",
         "setExtremeHighLimit":1.7976931348623157E307,
         "setExtremeLowLimit":-1.7976931348623157E307,
         "setPermission":"",
         "tags":{
         },
         "textRenderer":{
            "type":"ANALOG",
            "useUnitAsSuffix":true,
            "unit":"",
            "renderedUnit":"",
            "format":"0.0"
         },
         "tolerance":0.0
      };
            
    createdMetaPoints.push(meta);
}

for(var k in snmpPoints) {
	var dpWrapper = snmpPoints[k];
	createMetaPointForDataPoint(dpWrapper);
}


//The next line allows this import to happen even if we're just clicking the validate checkbox on a script
JsonEmport.setImportDuringValidation( true );

JsonEmport.doImport(JSON.stringify({"dataPoints":createdMetaPoints}));

Phil. please what we need now to add something to the script to multiplying the final value x20. It is because the value is %, I think that will be better, if it is shown as a number i.e. 70% = 20x70=1400

I will keep in touch about it

Joel's suggestion would work if the value didn't have the unit encoded in the alphanumeric value, and if your locale is set for Double.parseDouble to expect commas for number formatting. One could create a meta point and parse out the value that way, i.e.

where p is the variable name for a alphanumeric context point,

var pieces = /(-?\d+?),(\d+).*/.exec(p.value);
return parseFloat( pieces[1] + "." + pieces[2] );

Then you could generate history and whatnot for your existing data. That may not be exactly what you need (you may need to change the decimal delimiter on the second line back to a comma (if so, you could also just capture it all together in the first line)) but it's close.